CN114122222B - Composite passivation layer, manufacturing method thereof and LED chip - Google Patents

Abstract

The invention provides a composite passivation layer, a manufacturing method thereof and an LED chip, wherein the composite passivation layer is arranged on an exposed surface of an epitaxial lamination of the LED chip, the composite passivation layer comprises a passivation bottom layer and a passivation top layer which are sequentially stacked, the refractive index of the passivation bottom layer is smaller than that of the passivation top layer, the passivation bottom layer is used for contacting the surface of the LED chip and enabling the surface of the LED chip to withstand a reverse electric field, and the passivation top layer is used as a film layer for contacting the LED chip with the outside and is used for reducing holes; thereby improving the high-stress resistance and avoiding the infiltration of water vapor.

Description

Composite passivation layer, manufacturing method thereof, and LED chip

technical field

The invention relates to the field of light-emitting diodes, in particular to a composite passivation layer, a manufacturing method thereof, and an LED chip.

Background technique

With the continuous development of the LED display market, since LED displays are often used in high-temperature and high-humidity environments, and the internal LED chips are often under reverse pressure, the application side proposes a proposal for the withstand voltage of the small-sized LED chips of the display. In order to meet higher requirements, it is usually verified by loading reverse voltage on the chip under 85% humidity and high temperature and high humidity of 85°C (and double 85 reverse voltage reliability experiment). The failure mode in this harsh environment is that after high temperature accelerates water vapor to penetrate into the chip, it will electrochemically react with the N-type GaN of the chip under the action of a high reverse electric field, causing burns. At present, the chip uses a passivation protective layer (usually made of SiO2) on the surface to isolate water vapor and prevent water vapor from penetrating into the chip.

However, the existing passivation protection layer usually uses silane (SiH4) and laughing gas (N2O) to react to generate insulating SiO2, and the film layer will inevitably be doped with some Si-N bonds (shown as a high refractive index to about 1.5 , the refractive index of pure SiO2 is 1.46). The bond energy of Si-N is lower than that of Si-O bond. In the double 85 reverse pressure reliability experiment, due to the reverse strong electric field, a large number of hot electrons are injected, and the hot electrons are released in accordance with the trapped holes. The energy breaks the bond, and the continuous deterioration leads to cracking of the film layer, and the infiltration of water vapor causes failure. Therefore, it is necessary to reduce the Si-N bond in the film layer by reducing the gas flow ratio of silane/laughing gas. However, as the gas flow ratio of silane/laughing gas decreases, the refractive index of the film layer continues to drop to 1.46 or even below 1.46. At this time, the micro-voids in the film layer increase (the refractive index in the micro-voids is 1, which will lower the refractive index of the entire film layer), and water vapor is more likely to infiltrate through the passivation protective layer. Therefore, if the refractive index is too high, the film layer will break under the action of the reverse pressure electric field, causing water vapor to infiltrate; if the refractive index is too low, water vapor will infiltrate through micropores, which cannot prevent water vapor from eroding the inside of the chip.

In view of this, in order to overcome the above-mentioned defects of flip-chip LED chips in the prior art, the inventor specially designed a composite passivation layer, its manufacturing method, and LED chip, and this case arose from this.

Contents of the invention

The object of the present invention is to provide a composite passivation layer and its manufacturing method, and LED chip, so as to improve the reverse strong electric field tolerance of the LED chip and prevent the entry of water vapor.

In order to achieve the above object, the technical scheme adopted in the present invention is as follows:

A composite passivation layer, as a protective film layer of the object, comprising: a passivation bottom layer and a passivation top layer stacked in sequence, and the refractive index of the passivation bottom layer is smaller than the refractive index of the passivation top layer; the passivation The bottom layer is used to contact the surface of the object and make it withstand the reverse electric field, and the passivation top layer is used as a film layer between the object and the outside world to reduce holes.

Preferably, an intermediate layer is also provided between the passivation bottom layer and the passivation top layer, and the refractive index of the intermediate layer is between the passivation bottom layer and the passivation top layer, for transitioning the passivation Mutual stress between bottom layer and passivated top layer.

Preferably, the refractive index of the passivation bottom layer is 1.40-1.50, inclusive;

The refractive index of the intermediate layer is 1.42-1.52, inclusive;

The refractive index of the passivated top layer is 1.45-1.55, inclusive.

Preferably, the composite passivation layer includes a transparent insulating material, such as silicon dioxide or the like.

Preferably, the manufacturing method includes the steps of:

Step S01, placing the protected object in the reaction chamber, and keeping the reaction chamber at a preheating temperature;

Step S02, injecting a mixed gas of silane and laughing gas into the cavity to form a passivation bottom layer, and the refractive index of the passivation bottom layer is 1.40-1.50, inclusive;

Step S03, increasing the mixing ratio of the introduced silane and laughing gas to form an intermediate layer, and the refractive index of the intermediate layer is 1.42-1.52, inclusive;

Step S04 , increasing the mixing ratio of the injected silane and laughing gas again to form a passivation top layer, and the refractive index of the passivation top layer is 1.45˜1.55, including the endpoint values.

Preferably, in step S02, the mixing ratio of silane and laughing gas is 2:320-6:320, including the endpoint value;

In step S03, the mixing ratio of silane and laughing gas is 2:320-2:50, including the endpoint value;

In step S04, the mixing ratio of the silane and laughing gas is 1:50-2:50, including the endpoints.

Preferably, in the steps S02 , S03 and S04 , nitrogen gas may also be introduced to bind excess oxygen ions.

The present invention also provides an LED chip, which is a LED chip with a horizontal structure, comprising:

Substrate;

An epitaxial stack disposed on the surface of the substrate, the epitaxial stack includes a first-type semiconductor layer, an active region, and a second-type semiconductor layer stacked in sequence along a first direction, and a local area of the epitaxial stack Etching part of the first-type semiconductor layer to form grooves and mesas; the first direction is perpendicular to the substrate, and is directed from the substrate to the epitaxial stack;

a first electrode stacked on a part of the surface of the groove and disposed away from the sidewall of the groove;

a second electrode laminated on a part of the surface of the mesa;

A composite passivation layer, which covers the exposed surface of the epitaxial stack; the composite passivation layer includes the above-mentioned composite passivation layer, and the passivation bottom layer contacts the exposed surface of the epitaxial stack of the LED chip, The passivation top layer serves as a film layer for the LED chip to be in contact with the outside world.

Preferably, a transparent conductive layer is further provided on the mesa, and the composite passivation layer covers the transparent conductive layer.

The present invention also provides a kind of LED chip, and it is the LED chip of vertical structure, comprises:

conductive substrate;

A bonding layer, a metal reflector, and an epitaxial stack disposed on the surface of the conductive substrate, the epitaxial stack includes a second-type semiconductor layer, an active region, and a first-type semiconductor layer stacked in sequence along the first direction, so The first direction is perpendicular to the conductive substrate, and is directed from the conductive substrate to the epitaxial stack;

a first electrode stacked on a surface of the first-type semiconductor layer facing away from the active region;

a second electrode stacked on the back of the conductive substrate;

A composite passivation layer covering the exposed surface of the epitaxial stack; the composite passivation layer includes the composite passivation layer described in any one of the above, and the passivation bottom layer contacts the epitaxial stack of the LED chip On the exposed surface, the passivation top layer serves as a film layer for the LED chip to be in contact with the outside world.

It can be seen from the above technical solutions that the composite passivation layer and the LED chip provided by the present invention are provided with a composite passivation layer on the exposed surface of the epitaxial laminate of the LED chip, wherein the composite passivation layer includes a passivation bottom layer stacked in sequence and Passivate the top layer, and the refractive index of the passivated bottom layer is smaller than the refractive index of the passivated top layer, the passivated bottom layer is used to contact the surface of the LED chip and make it withstand the reverse electric field, and the passivated top layer acts as an LED The film layer between the chip and the outside world is used to reduce holes; thereby improving the performance of high pressure resistance and avoiding the infiltration of water vapor.

Further, an intermediate layer is also provided between the passivation bottom layer and the passivation top layer, and the refractive index of the intermediate layer is between the passivation bottom layer and the passivation top layer, for transitioning the passivation The mutual stress between the bottom layer and the passivation top layer improves the protective effect of the composite passivation film layer.

In addition, the refractive index of the passivated bottom layer is 1.40-1.50, so that it is in a lower refractive index range, so that the reduction of the refractive index can reduce the number of Si-N bonds, and improve the performance of high reverse pressure resistance; the passivated top layer The refractive index is 1.45-1.55, so that it is in a relatively high refractive index range, thereby avoiding the increase of holes in the composite passivation film layer itself, and avoiding the entry of water vapor; at the same time, the refractive index of the intermediate layer is 1.42-1.52, which is very good The stress transition between the passivation bottom layer and the passivation top layer is realized, and the thickness of the film layer is increased.

It can be seen from the above technical solutions that the method for manufacturing the composite passivation layer provided by the present invention realizes the above-mentioned beneficial effects of the LED chip, and at the same time, its manufacturing process is simple and convenient, and it is convenient for production.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention, and those skilled in the art can also obtain other drawings according to the provided drawings without creative work.

FIG. 1 is a schematic structural view of a composite passivation layer provided in Embodiment 1 of the present invention;

Fig. 2 is the flow chart of the manufacturing method of the composite passivation layer provided by embodiment 1 of the present invention;

FIG. 3 is a schematic structural diagram of an LED chip with a horizontal structure provided in Embodiment 2 of the present invention;

4 is a schematic structural diagram of a vertically structured LED chip provided by Embodiment 3 of the present invention;

Explanation of symbols in the figure: 1. Substrate, 2. First-type semiconductor layer, 3. Active region, 4. Second-type semiconductor layer, 5. Transparent conductive layer, 6. Metal reflective layer, 7. Bonding layer, 8. Composite passivation layer, 81. Passivation bottom layer, 82. Intermediate layer, 83. Passivation top layer, 9. Second electrode, 10. First electrode, 11. Conductive substrate.

Detailed ways

In order to make the content of the present invention clearer, the content of the present invention will be further described below in conjunction with the accompanying drawings. The invention is not limited to this specific example. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1

As shown in Figure 1, Embodiment 1 of the present invention aims to provide a composite passivation layer 8, which is used as a protective film layer for the object, including: a passivation bottom layer 81 and a passivation top layer 83 stacked in sequence, and the passivation The refractive index of the bottom layer 81 is smaller than the refractive index of the passivation top layer 83; the passivation bottom layer 81 is used to contact the surface of the object and make it withstand the reverse electric field, and the passivation top layer 83 serves as a film layer for the object to contact the outside world , to reduce porosity.

In this embodiment, an intermediate layer 82 is also provided between the passivation bottom layer 81 and the passivation top layer 83, and the refractive index of the intermediate layer 82 is between the passivation bottom layer 81 and the passivation top layer 83. , for transitioning the mutual stress between the passivation bottom layer 81 and the passivation top layer 83 .

In this embodiment, the refractive index of the passivation bottom layer 81 is 1.40-1.50, including endpoint values;

The refractive index of the intermediate layer 82 is 1.42-1.52, inclusive;

The refractive index of the passivation top layer 83 is 1.45˜1.55, inclusive.

In this embodiment, the passivation bottom layer 81 has a thickness of 100˜5000 Å, including endpoints.

In this embodiment, the thickness of the intermediate layer 82 is 100˜5000 Å, inclusive.

In this embodiment, the thickness of the passivation top layer 83 is 100˜5000 Å, including the endpoint values.

In this embodiment, the composite passivation layer 8 includes a transparent insulating material, such as silicon dioxide or the like.

As shown in Figure 2, the present embodiment also provides a method for making the composite passivation layer 8, the method of making includes the following steps:

Step S01, placing the protected object in the reaction chamber, and keeping the reaction chamber at a preheating temperature;

Step S02, injecting a mixed gas of silane and laughing gas into the cavity to form a passivation bottom layer, and the refractive index of the passivation bottom layer is 1.40-1.50, and the thickness of the passivation bottom layer is 100-5000 Å, including the endpoints value;

Step S03, increasing the mixing ratio of the introduced silane and laughing gas to form an intermediate layer, and the refractive index of the intermediate layer is 1.42-1.52, and the thickness of the intermediate layer is 100-5000 Å, inclusive;

Step S04, increase the mixing ratio of silane and laughing gas again to form a passivation top layer, and the refractive index of the passivation top layer is 1.45-1.55, and the thickness of the passivation top layer is 100-5000 Å, including the endpoints value.

In this embodiment, in step S02, the mixing ratio of silane and laughing gas is 2:320 to 6:320, including the endpoint values;

In step S03, the mixing ratio of silane and laughing gas is 2:320-2:50, including the endpoint value;

In step S04, the mixing ratio of the silane and laughing gas is 1:50-2:50, including the endpoints.

In this embodiment, in the steps S02 , S03 and S04 , nitrogen gas may also be introduced to bind excess oxygen ions.

It can be seen from the above technical solutions that the composite passivation layer provided by the embodiment of the present invention includes a passivation bottom layer and a passivation top layer stacked in sequence, and the refractive index of the passivation bottom layer is smaller than that of the passivation top layer, so The passivation bottom layer is used to contact and protect the surface of the object and make it withstand the reverse electric field, and the passivation top layer is used as a film layer to protect the object from contact with the outside world, and is used to reduce holes; thereby improving the high reverse pressure resistance and avoiding water vapor infiltration.

Further, an intermediate layer is also provided between the passivation bottom layer and the passivation top layer, and the refractive index of the intermediate layer is between the passivation bottom layer and the passivation top layer, for transitioning the passivation The mutual stress between the bottom layer and the passivation top layer improves the protective effect of the composite passivation film layer.

In addition, the refractive index of the passivated bottom layer is 1.40-1.50, so that it is in a lower refractive index range, so that the reduction of the refractive index can reduce the number of Si-N bonds, and improve the performance of high reverse pressure resistance; the passivated top layer The refractive index is 1.45-1.55, so that it is in a relatively high refractive index range, thereby avoiding the increase of holes in the composite passivation film layer itself, and avoiding the entry of water vapor; at the same time, the refractive index of the intermediate layer is 1.42-1.52, which is very good The stress transition between the passivation bottom layer and the passivation top layer is realized, and the thickness of the film layer is increased.

It can be known from the above technical solutions that the manufacturing method of the composite passivation layer provided by the embodiment of the present invention realizes the above-mentioned beneficial effects of the LED chip, and at the same time, its manufacturing process is simple and convenient, and is convenient for production.

Example 2

As shown in Figure 3, an embodiment of the present invention provides an LED chip, which is a LED chip with a horizontal structure, including:

substrate1;

An epitaxial stack disposed on the surface of the substrate, the epitaxial stack includes a first-type semiconductor layer 2, an active region 3, and a second-type semiconductor layer 4 stacked in sequence along a first direction, and the epitaxial stack Partial area of the first-type semiconductor layer 2 is etched to form grooves and mesas; the first direction is perpendicular to the substrate, and is directed from the substrate to the epitaxial stack;

a first electrode 10, which is laminated on a part of the surface of the groove and is arranged away from the sidewall of the groove;

The second electrode 9 is stacked on a part of the surface of the mesa;

Composite passivation layer, 8, which covers the exposed surface of the epitaxial stack; the composite passivation layer 8 adopts the composite passivation layer described in Embodiment 1, and the passivation bottom layer 81 contacts the epitaxial layer of the LED chip On the exposed surface of the stack, the passivation top layer 93 is used as a film layer for the LED chip to be in contact with the outside world.

In this embodiment, a transparent conductive layer 5 is further provided on the mesa, and the composite passivation layer 8 covers the transparent conductive layer 5 .

The second electrode 9 mainly includes a pad portion, and the pad portion is mainly used for external wiring during front electrode packaging. The pads of the front electrodes can be designed in different shapes according to the actual wire bonding needs, such as cylindrical or square or other polygonal shapes. As a preferred embodiment, the front electrode may further include an extension part extending from the pad, the extension part may be formed in a predetermined pattern shape, and the extension part may have various shapes, specifically a strip shape.

The first electrode 10 and the second electrode 9 are preferably made of metal materials. The pad portion and the extension portion of the second electrode 9 may also include a metal material to form a good ohmic contact with the semiconductor epitaxial material.

It should be noted that the epitaxial stack is a semiconductor barrier stack obtained by MOCVD or other growth methods, and the semiconductor barrier stack is able to provide conventional radiation such as ultraviolet, blue, green, yellow, red, infrared light, etc. The specific semiconductor materials can be 200-950nm materials, such as common nitrides, specifically, such as gallium nitride-based semiconductor barrier stacks, and gallium nitride-based barrier stacks are often doped with aluminum, indium, etc. Elements, mainly provide radiation in the 200-550nm band; or common AlGaInP-based or AlGaAs-based semiconductor barrier stacks, mainly provide radiation in the 550-950nm band. The semiconductor barrier stack mainly includes a second-type semiconductor layer, an active region, and a first-type semiconductor layer. The first-type semiconductor layer and the second-type semiconductor layer can be respectively n-type doped or p-type doped to realize material layers that at least respectively provide electrons or holes. The n-type semiconductor layer may be doped with an n-type dopant such as Si, Ge, or Sn, and the p-type doped semiconductor layer may be doped with a p-type dopant such as Mg, Zn, Ca, Sr, or Ba. The second-type semiconductor layer, the active region, and the first-type semiconductor layer can be made of aluminum gallium indium nitride, gallium nitride, aluminum gallium nitrogen, aluminum indium phosphide, aluminum gallium indium phosphide, or gallium arsenide or aluminum gallium arsenide. form. The second-type semiconductor layer and the first-type semiconductor layer include a covering layer that provides electrons or holes, and may include other layer materials such as a current spreading layer, a window layer or an ohmic contact layer, etc., depending on the doping concentration or component content. Set to different layers. The active region is the region that provides electron and hole recombination to provide light radiation. Different materials can be selected according to different luminescent wavelengths. The active region can be a periodic structure of single quantum well or multiple quantum wells. By adjusting the composition ratio of semiconductor materials in the active region, it is expected to radiate light of different wavelengths.

It can be seen from the above technical solutions that the LED chip provided by the embodiment of the present invention is provided with a composite passivation layer on the exposed surface of the epitaxial stack of the LED chip, wherein the composite passivation layer includes a passivation bottom layer and a passivation top layer stacked in sequence. , and the refractive index of the passivation bottom layer is smaller than the refractive index of the passivation top layer, the passivation bottom layer is used to contact the surface of the LED chip and make it withstand the reverse electric field, and the passivation top layer serves as the connection between the LED chip and the outside world The contact film layer is used to reduce holes; thereby improving the performance of high reverse pressure resistance and avoiding the infiltration of water vapor.

Further, an intermediate layer is also provided between the passivation bottom layer and the passivation top layer, and the refractive index of the intermediate layer is between the passivation bottom layer and the passivation top layer, for transitioning the passivation The mutual stress between the bottom layer and the passivation top layer improves the protective effect of the composite passivation film layer.

In addition, the refractive index of the passivated bottom layer is 1.40-1.50, so that it is in a lower refractive index range, so that the reduction of the refractive index can reduce the number of Si-N bonds, and improve the performance of high reverse pressure resistance; the passivated top layer The refractive index is 1.45-1.55, so that it is in a relatively high refractive index range, thereby avoiding the increase of holes in the composite passivation film layer itself, and avoiding the entry of water vapor; at the same time, the refractive index of the intermediate layer is 1.42-1.52, which is very good The stress transition between the passivation bottom layer and the passivation top layer is realized, and the thickness of the film layer is increased.

Example 3

As shown in Figure 4, an embodiment of the present invention provides an LED chip, which is a vertically structured LED chip, including:

Conductive substrate 11;

The bonding layer 7, the metal mirror 6, and the epitaxial stack disposed on the surface of the conductive substrate 11, the epitaxial stack includes the second-type semiconductor layer 4, the active region 3, and the first stacked in sequence along the first direction. type semiconductor layer 2, the first direction is perpendicular to the conductive substrate 11, and is directed from the conductive substrate 11 to the epitaxial stack;

A first electrode 10 stacked on the surface of the first-type semiconductor layer 2 facing away from the active region 3;

The second electrode 9 is stacked on the back side of the conductive substrate 11;

A composite passivation layer 8, which covers the exposed surface of the epitaxial stack; the composite passivation layer 8 adopts the composite passivation layer described in Embodiment 1, and the passivation bottom layer contacts the epitaxial stack of the LED chip layer exposed surface, and the passivation top layer serves as a film layer for the LED chip to be in contact with the outside world.

The second electrode 9 in this embodiment is formed on the back side of the substrate 11 in the form of the entire surface. The substrate in this embodiment is a conductive support substrate, and the first electrode and the second electrode are formed on both sides of the conductive substrate to realize current flow. Flows vertically through the epitaxial stack, providing uniform current density.

The first electrode 10 and the second electrode 9 are preferably made of metal materials. The pad portion and the extension portion of the first electrode 9 may also include a metal material to form a good ohmic contact with the semiconductor epitaxial material.

In this embodiment, the metal reflector may be formed of at least one metal or alloy among Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au and Hf.

It should be noted that the epitaxial stack is a semiconductor barrier stack obtained by MOCVD or other growth methods, and the semiconductor barrier stack is able to provide conventional radiation such as ultraviolet, blue, green, yellow, red, infrared light, etc. The specific semiconductor materials can be 200-950nm materials, such as common nitrides, specifically, such as gallium nitride-based semiconductor barrier stacks, and gallium nitride-based barrier stacks are often doped with aluminum, indium, etc. Elements, mainly provide radiation in the 200-550nm band; or common AlGaInP-based or AlGaAs-based semiconductor barrier stacks, mainly provide radiation in the 550-950nm band. The semiconductor barrier stack mainly includes a second-type semiconductor layer, an active region, and a first-type semiconductor layer. The first-type semiconductor layer and the second-type semiconductor layer can be respectively n-type doped or p-type doped to realize material layers that at least respectively provide electrons or holes. The n-type semiconductor layer may be doped with an n-type dopant such as Si, Ge, or Sn, and the p-type doped semiconductor layer may be doped with a p-type dopant such as Mg, Zn, Ca, Sr, or Ba. The second-type semiconductor layer, the active region, and the first-type semiconductor layer can be made of aluminum gallium indium nitride, gallium nitride, aluminum gallium nitrogen, aluminum indium phosphide, aluminum gallium indium phosphide, or gallium arsenide or aluminum gallium arsenide. form. The second-type semiconductor layer and the first-type semiconductor layer include a covering layer that provides electrons or holes, and may include other layer materials such as a current spreading layer, a window layer or an ohmic contact layer, etc., depending on the doping concentration or component content. Set to different layers. The active area is the area that provides electron and hole recombination to provide light radiation. Different materials can be selected according to the different wavelengths of light emission. The active area can be a periodic structure of single quantum well or multiple quantum wells. By adjusting the composition ratio of semiconductor materials in the active region, it is expected to radiate light of different wavelengths.

It should be noted that the first electrode is disposed on the light-emitting side of the epitaxial stack. The first electrode mainly includes a pad part, and the pad part is mainly used for external wire bonding when the front electrode is packaged. The pads of the front electrodes can be designed in different shapes according to the actual wire bonding needs, such as cylindrical or square or other polygonal shapes. As a preferred embodiment, the front electrode may further include an extension part extending from the pad, the extension part may be formed in a predetermined pattern shape, and the extension part may have various shapes, specifically a strip shape.

It can be seen from the above technical solutions that the LED chip provided by the embodiment of the present invention is provided with a composite passivation layer on the exposed surface of the epitaxial stack of the LED chip, wherein the composite passivation layer includes a passivation bottom layer and a passivation top layer stacked in sequence. , and the refractive index of the passivation bottom layer is smaller than the refractive index of the passivation top layer, the passivation bottom layer is used to contact the surface of the LED chip and make it withstand the reverse electric field, and the passivation top layer serves as the connection between the LED chip and the outside world The contact film layer is used to reduce holes; thereby improving the performance of high reverse pressure resistance and avoiding the infiltration of water vapor.

Further, an intermediate layer is also provided between the passivation bottom layer and the passivation top layer, and the refractive index of the intermediate layer is between the passivation bottom layer and the passivation top layer, for transitioning the passivation The mutual stress between the bottom layer and the passivation top layer improves the protective effect of the composite passivation film layer.

In addition, the refractive index of the passivated bottom layer is 1.40-1.50, so that it is in a lower refractive index range, so that the reduction of the refractive index can reduce the number of Si-N bonds, and improve the performance of high reverse pressure resistance; the passivated top layer The refractive index is 1.45-1.55, so that it is in a relatively high refractive index range, thereby avoiding the increase of holes in the composite passivation film layer itself, and avoiding the entry of water vapor; at the same time, the refractive index of the intermediate layer is 1.42-1.52, which is very good The stress transition between the passivation bottom layer and the passivation top layer is realized, and the thickness of the film layer is increased.

Each embodiment in this specification is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same and similar parts of each embodiment can be referred to each other.

It should also be noted that in this article, relational terms such as first and second etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that these entities or operations Any such actual relationship or order exists between. Moreover, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that an article or device comprising a set of elements includes not only those elements but also other elements not expressly listed, Or also include elements inherent in the article or device. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in an article or device comprising the aforementioned element.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the application. Therefore, the present application will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (8)

1. A composite passivation layer, as the protective film layer of the object, is characterized in that, comprises: the passivation bottom layer and passivation top layer stacked successively, and the refractive index of described passivation bottom layer is less than the refraction of described passivation top layer rate; the passivation bottom layer is used to contact the surface of the object and make it withstand the reverse electric field, and the passivation top layer is used as a film layer for the object to contact the outside world to reduce holes; Wherein, an intermediate layer is also provided between the passivation bottom layer and the passivation top layer, and the refractive index of the intermediate layer is between the passivation bottom layer and the passivation top layer, for transitioning the passivation bottom layer and the mutual stress between the passivation top layer; Moreover, the refractive index of the passivation bottom layer is 1.40-1.50, including the endpoint values; The refractive index of the intermediate layer is 1.42-1.52, inclusive; The refractive index of the passivated top layer is 1.45-1.55, inclusive. 2. The composite passivation layer according to claim 1, characterized in that, the composite passivation layer comprises a transparent insulating material. 3. A preparation method for a composite passivation layer, for making the composite passivation layer described in any one of claims 1 to 2, characterized in that, the preparation method comprises the steps: Step S01, placing the protected object in the reaction chamber, and keeping the reaction chamber at a preheating temperature; Step S02, injecting a mixed gas of silane and laughing gas into the cavity to form a passivation bottom layer, and the refractive index of the passivation bottom layer is 1.40-1.50, inclusive; Step S03, increasing the mixing ratio of the introduced silane and laughing gas to form an intermediate layer, and the refractive index of the intermediate layer is 1.42-1.52, inclusive; Step S04 , increasing the mixing ratio of the injected silane and laughing gas again to form a passivation top layer, and the refractive index of the passivation top layer is 1.45˜1.55, including the endpoint values. 4. the manufacture method of composite passivation layer according to claim 3, is characterized in that, In step S02, the mixing ratio of silane and laughing gas is 2:320-6:320, including the endpoint value; In step S03, the mixing ratio of silane and laughing gas is 2:320-2:50, including the endpoint value; In step S04, the mixing ratio of the silane and laughing gas is 1:50-2:50, including the endpoints. 5 . The method for fabricating a composite passivation layer according to claim 3 , characterized in that, in the steps S02 , S03 and S04 , nitrogen gas can also be introduced to combine excess oxygen ions. 6 . 6. A kind of LED chip, it is the LED chip of horizontal structure, it is characterized in that, comprises: Substrate; An epitaxial stack disposed on the surface of the substrate, the epitaxial stack includes a first-type semiconductor layer, an active region, and a second-type semiconductor layer stacked in sequence along a first direction, and a local area of the epitaxial stack Etching part of the first-type semiconductor layer to form grooves and mesas; the first direction is perpendicular to the substrate, and is directed from the substrate to the epitaxial stack; a first electrode stacked on a part of the surface of the groove and disposed away from the sidewall of the groove; a second electrode laminated on a part of the surface of the mesa; A composite passivation layer covering the exposed surface of the epitaxial stack; the composite passivation layer comprises the composite passivation layer according to any one of claims 1 to 2, and the passivation bottom layer contacts the LED chip The exposed surface of the epitaxial stack is used, and the passivation top layer is used as a film layer for the LED chip to be in contact with the outside world. 7. The LED chip according to claim 6, wherein a transparent conductive layer is further provided on the mesa, and the composite passivation layer covers the transparent conductive layer. 8. A kind of LED chip, it is the LED chip of vertical structure, is characterized in that, comprises: conductive substrate; A bonding layer, a metal reflector, and an epitaxial stack disposed on the surface of the conductive substrate, the epitaxial stack includes a second-type semiconductor layer, an active region, and a first-type semiconductor layer stacked in sequence along the first direction, so The first direction is perpendicular to the conductive substrate, and is directed from the conductive substrate to the epitaxial stack; a first electrode stacked on the surface of the first-type semiconductor layer facing away from the active region; a second electrode stacked on the back of the conductive substrate; A composite passivation layer covering the exposed surface of the epitaxial stack; the composite passivation layer comprises the composite passivation layer according to any one of claims 1 to 2, and the passivation bottom layer contacts the LED chip The exposed surface of the epitaxial stack, and the passivation top layer is used as a film layer for the LED chip to be in contact with the outside world.

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