CN113066852B - Sensing Power Semiconductor Devices - Google Patents

Abstract

The invention discloses a sensing power semiconductor device, wherein a main transistor has a first current path, a secondary transistor has a second current path for monitoring the current in the first current path, and the sensing transistor has a third current path, It is used to monitor the current in the second current path, and finally the sensing transistor can indirectly monitor the current in the first current path; the temperature measuring diode has a fourth current path for monitoring the chip temperature of the power semiconductor, and the device of the present invention will The current in the sensing transistor is further reduced in order to increase the sampling resistance, improve the accuracy, and reduce the waste of energy.

Description

Sensing Power Semiconductor Devices

technical field

The invention relates to the technical field of power semiconductor devices, in particular to a power semiconductor device integrating current monitoring and temperature monitoring.

Background technique

In the end application, some manufacturers want to monitor the current flowing through the power device for fault detection and current size control. The structures used to measure current in power devices are often referred to as sensing field effect transistors. The sense field effect transistors are small field effect transistors separate from the main power field effect transistors. The sensing field effect transistor is generally configured to generate a voltage corresponding to the current in the main field effect transistor in order to provide current sensing, and may be integrated into the same semiconductor chip as the main field effect transistor.

At present, manufacturers hope to further improve the accuracy of monitoring current. This needs to further reduce the current in the sensing field effect transistor, so as to increase the sampling resistance, improve the accuracy, and reduce the waste of energy.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies in the prior art, and to provide a power semiconductor device that can improve the accuracy of monitoring current.

According to the technical solution provided by the present invention, a sensing power semiconductor device includes:

a main transistor, which has a first current path, and the current flows from the drain pad through the first drain metal and the first source metal of the main transistor, and finally enters the first source pad;

A secondary transistor with a second current path for monitoring the current in the first current path, the current flows from the drain pad through the second drain metal, the second source metal of the secondary transistor, and finally enters the first source pad;

a sense transistor having a third current path for monitoring current in the second current path, the current flows from the drain pad through the third drain metal, the third source metal of the sense transistor, and finally into the second source pad;

The temperature measuring diode has a fourth current path for monitoring the chip temperature of the power semiconductor, and the current flows from the anode pad through the anode metal and the cathode metal of the temperature measuring diode, and finally enters the drain pad.

Further, the first drain metal of the main transistor, the second drain metal of the sub transistor, the third drain metal of the sensing transistor, the negative metal of the temperature measuring diode and the drain pad are electrically coupled to each other; A source metal, the second source metal of the secondary transistor and the first source pad are electrically coupled to each other; the third source metal of the sensing transistor is electrically coupled to each other through the first metal connection line and the second source pad; The anode metal of the temperature measuring diode is electrically coupled to each other through the second metal connection line and the anode pad; the first gate metal and the first gate pad of the main transistor are electrically coupled to each other; the second gate metal of the secondary transistor, the sensing The third gate metal and the second gate pad of the transistor are electrically coupled to each other.

Further, the ratio of the area of the source region of the main transistor to the sub-transistor is n:1, and the range of n is 1<n≤1000; the ratio of the area of the source region of the sub-transistor to the sensing transistor is m:1, The range of m is 1<m≦1000.

Further, the main transistor, the auxiliary transistor and the sensing transistor have the same power semiconductor structure.

Further, the main transistor includes: a first conductive type substrate is provided above the drain pad, a first conductive type epitaxial layer is provided above the first conductive type substrate, and a first conductive type epitaxial layer is provided above the first conductive type substrate. A second conductivity type body region is provided on the surface of a conductivity type epitaxial layer, a first conductivity type source region is provided on the surface of the second conductivity type body region, and a second conductivity type body region is provided in the second conductivity type body region A conductive type source region, a trench is provided on the surface of the first conductive type source region, the trench penetrates the first conductive type source region and the second conductive type body region, and then enters the first conductive type epitaxial layer , the trenches are parallel to each other and equally spaced in stripes, the sidewalls and the bottom of the trenches are provided with a field oxide layer, the field oxide layer wraps the shielding gate polysilicon, and the two sides on the top of the shielding gate polysilicon A gate polysilicon is provided on the side, and the gate polysilicon is insulated from the first conductivity type source region, the second conductivity type body region, and the first conductivity type epitaxial layer through the gate oxide layer, and is in the trench and the first conductivity type. An insulating dielectric layer is provided above the source region, a first source metal is provided above the insulating dielectric layer, and the first source metal penetrates the insulating dielectric layer and the first conductive type source region and the second conductive type source ohmic contact.

Further, for an N-type power semiconductor device, the first conductivity type is N-type, and the second conductivity type is P-type; for a P-type power semiconductor device, the first conductivity type is P-type, and the The second conductivity type is N-type.

Further, the first gate metal of the main transistor surrounds the periphery of the power semiconductor device; the first gate metal is connected to the gate polysilicon through a through hole.

Further, the sensing transistor and the temperature measuring diode are located at the center of the power semiconductor device.

Compared with the conventional device, there is no secondary transistor; the invention discloses a sensing power semiconductor device, wherein the primary transistor has a first current path, and the secondary transistor has a second current path for monitoring the current in the first current path , the sensing transistor has a third current path for monitoring the current in the second current path, and finally the sensing transistor can indirectly monitor the current in the first current path; wherein the temperature sensing diode has a fourth current path for monitoring Die temperature of power semiconductors.

The present invention has the following advantages:

1. When the device of the present invention works, the current flowing through the sub-transistor works externally, and the current flowing through the sub-transistor will not be wasted.

2. The sampling current required by the sensing transistor of the device of the present invention is much smaller than that of the traditional device, so the energy consumed in sampling is relatively small.

3. The present invention can use a sampling resistor with a larger resistance value to improve the sampling accuracy.

4. The device of the present invention integrates a temperature measuring diode, which can monitor the core temperature of the device and ensure that the device works within a safe range.

Description of drawings

FIG. 1 is a schematic diagram of the circuit structure of the device of the present invention.

FIG. 2 is a schematic diagram of the chip surface structure of the device of the present invention.

FIG. 3 is a schematic diagram of the cell structure of the power semiconductor of the device of the present invention.

Detailed ways

It should be noted that the embodiments of the present invention and the features of the embodiments may be combined with each other under the condition of no conflict. The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only Embodiments of some, but not all, of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that the terms "first", "second" and the like in the description and claims of the present invention and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances for the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having", and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those expressly listed Rather, those steps or units may include other steps or units not expressly listed or inherent to these processes, methods, products or devices.

Embodiment 1;

A sensing power semiconductor device, as shown in Figure 1, includes:

The main transistor 1 has a first current path 11, and the current flows from the drain pad 5 through the first drain metal 15 and the first source metal 16 of the main transistor 1, and finally enters the first source pad 8;

The secondary transistor 2 has a second current path 12 for monitoring the current in the first current path 11 , and the current flows from the drain pad 5 through the second drain metal 17 and the second source metal 18 of the secondary transistor 2 , and finally enter the first source pad 8;

The sensing transistor 3 has a third current path 13 for monitoring the current in the second current path 12 , the current flows from the drain pad 5 through the third drain metal 19 , the third source electrode of the sensing transistor 3 The metal 20 finally enters the second source pad 9;

The temperature measuring diode 4 has a fourth current path 14 for monitoring the chip temperature of the power semiconductor. The current flows from the anode pad 10 through the anode metal 22 and the cathode metal 21 of the temperature measuring diode 4 , and finally enters the drain pad 5 .

As shown in FIG. 2 , the first drain metal 15 of the main transistor 1 , the second drain metal 17 of the sub-transistor 2 , the third drain metal 19 of the sensing transistor 3 , the negative electrode metal 21 of the temperature measuring diode 4 and the drain metal The electrode pads 5 are electrically coupled to each other; the first source metal 16 of the main transistor 1 , the second source metal 18 of the secondary transistor 2 and the first source pad 8 are electrically coupled to each other; the third source of the sensing transistor 3 The metals 20 are electrically coupled to each other through the first metal connecting wire 25 and the second source pad 9; the anode metal 22 of the temperature measuring diode 4 is electrically coupled to each other through the second metal connecting wire 24 and the anode pad 10; A gate metal 23 and the first gate pad 6 are electrically coupled to each other; the second gate metal 27 of the sub-transistor 2, the third gate metal 26 and the second gate pad 7 of the sense transistor 3 are electrically coupled to each other .

The ratio of the area of the source region of the main transistor 1 to the sub-transistor 2 is 100:1; the ratio of the area of the source region of the sub-transistor 2 to the sensing transistor 3 is 100:1.

The main transistor 1 , the sub transistor 2 and the sensing transistor 3 have the same power semiconductor structure. As shown in FIG. 3 , an N-type substrate 28 is provided above the drain pad 5 . An N-type epitaxial layer 29 is provided above the substrate 28, a P-type body region 35 is provided on the surface of the N-type epitaxial layer, and an N-type source region 37 is provided on the surface of the P-type body region 35. The P-type body region 35 is provided with a P-type source region 36, and a trench 30 is provided on the surface of the N-type source region 37, and the trench 30 penetrates the N-type source region 37 and the P-type body region 35. Then enter the N-type epitaxial layer 29, the trenches 30 are parallel to each other in stripes and distributed at equal intervals, the sidewalls and the bottom of the trenches 30 are provided with a field oxide layer 31, and the field oxide layer 31 wraps the shielding The gate polysilicon 32 is provided with gate polysilicon 33 on both sides of the top of the shielded gate polysilicon 32. The gate polysilicon 33 is connected to the N-type source region 37, the P-type body region 35, and the N-type epitaxial layer through the gate oxide layer 34. 29 are insulated from each other, an insulating dielectric layer 38 is provided above the trench 30 and the N-type source region 37, and a first source metal 16 is provided above the insulating dielectric layer 38, and the first source metal 16 penetrates through the insulating medium layer 38 and is in ohmic contact with the N-type source region 37 and the second-conductivity-type source region 36 .

The sensing transistor 3 and the temperature measuring diode 4 are located at the center of the power semiconductor device; since the current at the center of the power semiconductor device is the most uniform, the sensing transistor 3 can be arranged at this position to improve the current detection accuracy; the temperature measuring diode 4 is located in the center of the power semiconductor device, which can also improve the temperature detection accuracy;

The first gate metal 23 of the main transistor 1 surrounds the periphery of the power semiconductor device; in order to facilitate the connection between the first gate metal 23 and the gate polysilicon 33, the first gate metal 23 is connected to the gate through a through hole Very polysilicon 33.

Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be Modifications or equivalent substitutions without departing from the spirit and scope of the technical solutions of the present invention should be included in the scope of the claims of the present invention.

Claims (5)

1. A sensing power semiconductor device, characterized in that, comprising: A main transistor (1) having a first current path (11), current flowing from a drain pad (5) through a first drain metal (15), a first source metal (16) of the main transistor (1) , and finally enter the first source pad (8); A secondary transistor (2) having a second current path (12) for monitoring the current in the first current path (11), the current flowing from the drain pad (5) through the second drain of the secondary transistor (2) The electrode metal (17), the second source metal (18), and finally enter the first source pad (8); A sensing transistor (3) having a third current path (13) for monitoring the current in the second current path (12), the current flowing from the drain pad (5) through the third current path of the sensing transistor (3) Three drain metal (19), third source metal (20), and finally enter the second source pad (9); A temperature measuring diode (4), which has a fourth current path (14) for monitoring the chip temperature of the power semiconductor, the current flows from the anode pad (10) through the anode metal (22) and the cathode of the temperature measuring diode (4) Metal (21), which finally enters the drain pad (5); The first drain metal (15) of the main transistor (1), the second drain metal (17) of the secondary transistor (2), the third drain metal (19) of the sensing transistor (3), the temperature measuring diode ( 4) The negative metal (21) and the drain pad (5) are electrically coupled to each other; the first source metal (16) of the main transistor (1), the second source metal (18) of the secondary transistor (2) and The first source pads (8) are electrically coupled to each other; the third source metal (20) of the sense transistor (3) is electrically coupled to each other through the first metal connection line (25) and the second source pad (9) ; the anode metal ( 22 ) of the temperature measuring diode ( 4 ) are electrically coupled to each other through the second metal connecting line ( 24 ) and the anode pad ( 10 ); the first gate metal ( 23 ) of the main transistor ( 1 ) and the first The gate pads (6) are electrically coupled to each other; the second gate metal (27) of the secondary transistor (2), the third gate metal (26) of the sense transistor (3) and the second gate pad (7) ) are electrically coupled to each other; The ratio of the area of the source region of the main transistor (1) to the sub-transistor (2) is n:1, and the range of n is 1<n≤1000; the source of the sub-transistor (2) and the sensing transistor (3) The area ratio is m:1, and the range of m is 1<m≤1000; The sensing transistor (3) and the temperature measuring diode (4) are located at the center of the power semiconductor device; The main transistor (1) and the auxiliary transistor (2) are arranged in different regions; The first source metal (16) of the main transistor (1) and the second source metal (18) of the secondary transistor (2) are respectively arranged in different source regions, and the third source metal of the sensing transistor (3) The source metal (20) and the anode metal (22) of the temperature measuring diode (4) are located at the center of the power semiconductor device. 2 . The sensing power semiconductor device according to claim 1 , wherein the main transistor ( 1 ), the secondary transistor ( 2 ) and the sensing transistor ( 3 ) have the same power semiconductor structure. 3 . 3. A sensing power semiconductor device according to claim 2, wherein, The main transistor (1) includes: A first conductive type substrate (28) is provided above the drain pad (5), a first conductive type epitaxial layer (29) is provided above the first conductive type substrate (28), A second conductivity type body region (35) is provided on the surface of the first conductivity type epitaxial layer, a first conductivity type source region (37) is provided on the surface of the second conductivity type body region (35), A second conductivity type source region (36) is provided in the second conductivity type body region (35), a trench (30) is provided on the surface of the first conductivity type source region (37), and the trench (30) penetrate the first conductivity type source region (37) and the second conductivity type body region (35), and then enter the first conductivity type epitaxial layer (29), the trenches (30) are parallel to each other in the shape of stripes and are equally spaced, the sidewalls and bottom of the trench (30) are provided with a field oxide layer (31), the field oxide layer (31) wraps the shielding gate polysilicon (32), and the shielding gate polysilicon ( 32) Gate polysilicon (33) is provided on both sides of the top, and the gate polysilicon (33) is connected to the first conductivity type source region (37) and the second conductivity type body region (35) through the gate oxide layer (34) , the first conductivity type epitaxial layers (29) are insulated from each other, an insulating medium layer (38) is provided above the trench (30) and the first conductivity type source region (37), and the insulating medium layer (38) ) is provided with a first source metal (16), the first source metal (16) penetrates the insulating dielectric layer (38) and the first conductivity type source region (37), the second conductivity type source region ( 36) Ohmic contact. 4. A sensing power semiconductor device according to claim 3, characterized in that, For an N-type power semiconductor device, the first conductivity type is N-type, and the second conductivity type is P-type; for a P-type power semiconductor device, the first conductivity type is P-type, and the second conductivity type is P-type for the N type. 5. A sensing power semiconductor device according to claim 3, characterized in that, The first gate metal (23) of the main transistor (1) surrounds the periphery of the power semiconductor device; the first gate metal (23) is connected to the gate polysilicon (33) through a through hole.

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