CN105374677B - A kind of method that high electron mobility field-effect transistor is prepared on large scale Si substrates - Google Patents

Abstract

The invention provides a method for preparing a high electron mobility field-effect transistor (HEMT) on a large-size Si substrate, in particular to a method for preparing a HEMT using a carbon nanotube as a periodic dielectric mask and using a selective area epitaxy (SAG) method. Cracked, High Crystal Quality AlGaN/GaN HEMT Device Approach. The AlN nucleation layer and the AlGaN seed layer are grown on the Si substrate by metal organic chemical vapor phase epitaxy; then the low-pressure chemical vapor deposition (LPCVD) is used to grow neatly arranged multilayer carbon nanotubes, through growth and braiding, and finally Form a continuous carbon nanotube film; on this basis, the selective area epitaxy (SAG) method is used to limit the growth of the GaN epitaxial layer in the area without a dielectric mask by using the selectivity of GaN growth on the dielectric mask and the substrate. Formation of discrete windows to release tensile stress throughout the epitaxial layer; Al _y1 Ga _1‑y1 N/GaN superlattice or AlN/Al _y1 Ga _1‑y1 N/GaN superlattice with multi-period Al compositional gradient As a stress control layer, a GaN epitaxial layer with no cracks and high crystal quality is obtained. On this basis, AlGaN/GaN HEMT devices are prepared.

Description

A method for fabricating high electron mobility field-effect transistors on large-size Si substrates method

technical field

The invention relates to a method for preparing a high electron mobility [field effect] transistor (HEMT, high electron mobility transistor) on a large-size Si substrate. In particular, it relates to a method of using carbon nanotubes as a periodic dielectric mask and using selective area growth (selective area growth, SAG) method to prepare AlGaN/GaN HEMT devices with no cracks and high crystal quality, which belongs to semiconductor optoelectronic technology field.

Background technique

High Electron Mobility Field Effect Transistor (HEMT), also known as modulation-doped field effect transistor (MODFET, modulation-doped field effect transistor), is a dual A field-effect transistor (FET) that conducts electricity through a dimensional electron gas. Because there are no impurities in the channel, there is basically no impact of ionized impurity scattering on electron movement, so the electron mobility is higher. The working principle of HEMT is to change the channel current between the source and the drain by controlling the change of the gate voltage, so as to achieve the purpose of amplifying the signal. Its advantages are high frequency and low noise characteristics. HEMTs are already used in receiving circuits for satellite TV, mobile communications, military communications and radar systems. Since GaAs-based HEMT was successfully developed in 1980, it has developed rapidly. GaAs-based HEMTs have been widely used in radio frequency, microwave and millimeter wave low frequency bands. InP devices have a higher operating frequency and lower noise than GaAs HEMTs, and are used in the millimeter wave high frequency band and submillimeter wave frequency band. GaN HEMT devices are characterized by high temperature resistance and high power, and have great application prospects, especially in the dominant position in 10-40GHz.

AlGaN/GaN HEMT has a large bandgap width (3.4eV), high breakdown voltage (3.3MV/cm), high saturation electron velocity (2.8*10 ⁷ s ^-1 ) and two-dimensional electron gas surface of GaN as the channel layer. High density (10 ¹³ cm ² ) and other characteristics lead to the development of GaN-based HEMT research towards higher operating frequency, greater output power, higher operating temperature and practical application. GaN-based HEMTs can also be used in high-speed switching integrated circuits and high-voltage DC-DC converters. AlGaN/GaN HEMTs are grown on semi-insulating (0001) Si-faced SiC or (0001) sapphire substrates, a layer of semi-insulating GaN (about 2 μm) channel layer is grown after the nucleation layer, and then undoped AlGaN spacer layer, Si-doped AlGaN and undoped AlGaN barrier layer. Two-dimensional electron gas is formed at the channel layer/isolating layer interface. The large size and low price of Si substrate can reduce the cost of epitaxial growth. Compared with the heat-insulating sapphire substrate with high hardness and poor thermal conductivity, the processing technology such as substrate thinning is simplified, and the cost of device manufacturing process is reduced.

The difficulty of growing GaN on Si by metalorganic vapor phase epitaxy (MOVPE) lies in the fact that the lattice mismatch between the GaN wurtzite structure (0001) and the diamond structure Si (111) substrate is 20.4%. A large number of dislocations are generated; the thermal mismatch between GaN and Si is as high as 56%, and the epitaxial layer will bear a large tensile stress during the cooling project after the epitaxial growth. Since the thickness of the epitaxial layer is much smaller than that of the substrate, microcracks will occur in the epitaxial layer, which seriously affects the characteristics of GaN devices. When GaN is directly grown on the Si substrate, NH ₃ is easy to react with the substrate Si to form amorphous SiN on the substrate surface, which affects the growth quality of GaN. There is also a strong chemical reaction between the metal Ga and the substrate Si, which will cause the substrate to dissolve back, thereby destroying the flatness of the interface. When growing at high temperature, Si in the substrate will diffuse to the surface of the buffer layer. If not properly controlled, it will affect the growth mode of GaN, thereby destroying the crystal quality. In addition, since Si is a non-polar semiconductor, some problems related to the polarity of the compound will arise when GaN, AlN or other polar semiconductors are grown on it.

The use of a suitable buffer layer is an effective means to solve the problems of lattice mismatch, Si diffusion and polarity when growing GaN on Si substrates, and it can also relieve the stress in the film to a certain extent. Many methods have been tried for this reason, such as composite buffer layers such as AlAs, AlN, and AlGaN/AlN. Among them, AlN has the best results, and its main advantage is that it can be grown in the same reaction chamber as GaN, and can avoid the formation of SiN during high temperature growth. Many solutions have been proposed based on its stress relief mechanism:

(1) Buffer layer stress compensation method: the buffer layer provides a compressive stress to the upper layer GaN to compensate the tensile stress caused by thermal mismatch. For example, using five gradient _{AlxGa1 -xN} (x=0.87, 0.67, 0.47, 0.27 and 0.07) buffer layers, the results show that the crack density is significantly reduced, and the optical properties are also greatly improved.

(2) Insertion layer stress clipping method: adjust the stress state inside the film through the insertion layer, or block the propagation of the tensile stress introduced from the substrate due to thermal mismatch. For example, the superlattice insertion layer method: insert 10 cycles of AlN/GaN superlattice as the insertion layer, and the total thickness of GaN growth is 2 μm. As the number of superlattice insertion layers increases, the tensile strain decreases. TEM shows that the dislocation density decreases with thickness.

However, the current mainstream insertion layer method cannot completely eliminate stress, and there are problems such as high defect density and warpage. Moreover, conventional ELOG (epitaxial lateral overgrowth, ELOG) technology, which is effective in reducing GaN dislocation density, is difficult to apply to AlGaN, because Al atoms have poor migration ability on the growth surface, and AlGaN will be deposited on the mask.

In the present invention, on a large-size Si substrate, carbon nanotubes are used as a periodic dielectric mask, and an AlGaN/GaN HEMT device with no cracks and high crystal quality is prepared by a selective area epitaxy (SAG) method, which can not only effectively solve the current problem The undesired stress and defects that still exist in the technology can effectively alleviate the warpage.

Contents of the invention

The invention provides a method for preparing a high electron mobility field-effect transistor (HEMT) on a large-size Si substrate. The technical scheme of the invention is as follows: on the Si substrate, (1) grow AlN nucleation layer and AlGaN seed layer. (2) Then, low pressure chemical vapor deposition (LPCVD, Low Pressure Chemical Vapor Deposition) is used, acetylene is used as the carrier gas, and 5nm Fe is used as the catalyst to grow neatly arranged multilayer carbon nanotubes. The diameter of the grown carbon nanotubes is 15 nm. Through growth and weaving, the carbon nanotube arrays arranged in parallel can finally form a continuous carbon nanotube film. (3) On this basis, the selective area epitaxy (SAG) method is adopted, and the selectivity of GaN growth on the dielectric mask and the substrate is used to limit the growth of the GaN epitaxial layer in the area without a concealed film to form a discrete window. The "controlled facet growth process" bends the dislocations, thereby reducing the threading dislocation density over the entire area, releasing the tensile stress in the entire epitaxial layer, and obtaining a GaN epitaxial layer with no cracks and high crystal quality. (4) On this basis, grow Al _y1 Ga _1-y1 N/GaN superlattice or AlN/Al _y1 Ga _1-y1 N/GaN superlattice with multi-period Al composition gradient as the stress control layer. (5) Finally prepare the AlGaN/GaN HEMT device. The method includes the following steps:

Step 1: In the metal organic compound vapor phase epitaxy reaction chamber, under the hydrogen (H ₂ ) atmosphere, on the Si substrate, at a temperature of 1000 ° C to 1500 ° C, feed TMAl as the source of group III, and NH ₃ as the source of group V , grow a 0.1-0.5 micron thick AlN nucleation layer; on this basis, at a temperature of 1000 ° C ~ 1500 ° C, feed TMAl, TMGa as the III source, _NH3 as the V source, and grow a 0.1-1 micron thick AlGaN seed crystal layer.

In the second step, a low-pressure chemical vapor deposition (LPCVD) method is used to grow neatly arranged multilayer carbon nanotubes. During the growth process, acetylene was used as the carrier gas, and Fe was used as the catalyst. The diameter of the grown carbon nanotubes is 15 nm. Through growth and weaving, a continuous carbon nanotube film is finally formed by parallel arrays of carbon nanotubes.

Step 3: In a hydrogen (H ₂ ) atmosphere, at 1000°C to 1500°C, feed TMGa as the Group III source and NH ₃ as the V group source. On this basis, use the selective area epitaxy (SAG) method to use GaN in The selectivity of the growth on the dielectric mask and the substrate limits the growth of the GaN epitaxial layer in the area without a dielectric mask, forming discrete windows, releasing the tensile stress in the entire epitaxial layer, and growing a 0.1-1 micron GaN merged layer.

Step 4: In a hydrogen (H ₂ ) atmosphere, at 1000°C to 1500°C, inject TMGa and TMAl as Group III sources, and NH ₃ as Group V sources to grow Al with a multi-period asymmetrical Al composition gradient _{The y1} Ga _1-y1 N/GaN superlattice or the AlN/Al _y1 Ga _1-y1 N/GaN superlattice is used as the stress control layer, and the period number of the superlattice is 1-20. The thickness of the superlattice well layer GaN is 1-5nm, the thickness of the superlattice Al _y1 Ga _1-y1 N barrier layer is 1-5nm, and the thickness of the superlattice AlN insertion layer is 1-5nm;

The Al composition y ₁ gradually decreases from 1 to 0 (0≤y1≤1) with the increase of the period number of the superlattice in the stress regulation layer.

Step 5, in a hydrogen (H ₂ ) atmosphere, at 1050° C. to 1200° C., feed TMGa as a group III source, and NH ₃ as a V group source to grow a 2-4 micron thick μ-GaN semi-insulating layer. Then pass through TMGa, TMAl as III source, NH ₃ as V source, SiH ₄ as n-type dopant source to grow undoped 5nm~15nm AlGaN isolation layer, 10nm~20nm Si-doped AlGaN and undoped AlGaN AlGaN barrier layer.

The invention discloses a method for preparing a high electron mobility field-effect transistor (HEMT) on a large-size Si substrate, using carbon nanotubes as a periodic dielectric mask, and adopting a selective area epitaxy (SAG) method to prepare crack-free, high-crystallinity High-quality AlGaN/GaN HEMT devices can not only effectively solve the stress and defects that still exist in the current technology, effectively alleviate warpage, but also effectively improve thermal conductivity.

Description of drawings

1 is a cross-sectional view of a novel structure AlGaN/GaN HEMT device using carbon nanotubes as a periodic dielectric mask and using an Al _y1 Ga _1-y1 N/GaN superlattice stress regulation layer in Embodiment 1 of the present invention;

2 is a cross-sectional view of an AlGaN/GaN HEMT device with a new structure using carbon nanotubes as a periodic dielectric mask and using AlN/Al _y1 Ga _1-y1 N/GaN superlattice in Embodiment 2 of the present invention;

Figure 3(a) is a general structure without using carbon nanotubes as a periodic dielectric mask and without using Al _y1 Ga _1-y1 N/GaN superlattice or AlN/Al _y1 Ga _1-y1 N/GaN superlattice SEM photos of AlGaN/GaN HEMT devices with stress regulation layer: Fig. 3(b) and (c) are SEM photos of AlGaN/GaN HEMT devices adopting the novel structure of Example 1 and Example 2 of the present invention.

Detailed ways

The invention provides a method for preparing a high electron mobility field effect transistor (HEMT) on a large-scale Si substrate. Using trimethylgallium (TMGa), trimethylaluminum (TMAl) as group III source, ammonia gas (NH ₃ ) as group V source, silane (SiH ₄ ) as n-type doping source, on Si substrate, An AlN nucleation layer and an AlGaN seed layer are grown at low temperature first. On this basis, creatively use carbon nanotubes as a periodic dielectric mask, adopt the selective area epitaxy (SAG) method, and design the structure of the stress control layer to obtain a crack-free, high-quality AlGaN epitaxial layer. And further prepare AlGaN/GaN HEMT devices.

Fig. 1 is a side cross-sectional view of an AlGaN/GaN HEMT device for realizing the present invention according to an embodiment of the present invention. 1 includes Si substrate 101, AlN nucleation layer and AlGaN seed layer 102, carbon nanotube mask 103, GaN merged layer 104; Al _y1 Ga _1-y1 N/GaN superlattice stress control layer 105, u - GaN (undoped GaN) semi-insulating layer 106 . u-AlGaN (undoped AlGaN) isolation layer 107 , n-AlGaN (n-doped AlGaN) and u-AlGaN (undoped AlGaN) barrier layer 108 .

Fig. 2 is a side cross-sectional view of an AlGaN/GaN HEMT device for realizing the present invention according to an embodiment of the present invention. 1 includes Si substrate 201, AlN nucleation layer and AlGaN seed layer 202, carbon nanotube mask 203, GaN merged layer 204; AlN/Al _y1 Ga _1-y1 N/GaN superlattice stress control layer 205 , u-GaN (undoped GaN) semi-insulating layer 206 . u-AlGaN (undoped AlGaN) isolation layer 207 , n-AlGaN (n-doped AlGaN) and u-AlGaN (undoped AlGaN) barrier layer 208 .

Among them, the periodic dielectric mask on the Si substrate adopts carbon nanotubes, and the stress regulation layer adopts AlGaN/AlGaN superlattice or AlN/AlGaN/GaN superlattice structure or other structures with gradually changing Al composition, as long as it satisfies The Al composition gradient principle can be used.

Example 1

Use Aixtron company, tightly coupled vertical reaction chamber MOCVD growth system. During the growth process, trimethylgallium (TMGa) and trimethylaluminum (TMAl) were used as Group III sources, ammonia gas (NH ₃ ) was used as Group V sources, silane (SiH ₄ ) was used as n-type dopant sources, and dimagnesocene (Cp ₂ Mg) as the p-type doping source, firstly heat the Si substrate 101 to 1080°C in the MOCVD reaction chamber, use TMGa, TMAl as the III source, and NH ₃ as the V source in the H ₂ atmosphere, A 0.1 micron-thick AlN nucleation layer is grown; then, at 1080° C. under H ₂ atmosphere, feed TMAl and TMGa as group III sources, and NH ₃ as V group source, and grow a 0.5 micron thick AlGaN seed layer 102 . Aligned multilayer carbon nanotubes were grown by low-pressure chemical vapor deposition (LPCVD). During the growth process, acetylene was used as the carrier gas, and 5nm Fe was used as the catalyst. The diameter of the grown carbon nanotubes is 15 nm. Through growth and weaving, finally a continuous carbon nanotube film 103 can be formed from parallel arrays of carbon nanotubes. At 1080°C under _H2 atmosphere, inject TMGa and TMAl as Group III source, and _NH3 as Group V source to grow 1 μm GaN merged layer 104; at 1080°C under _H2 atmosphere, inject TMGa and TMAl as Group III source , NH ₃ is used as the V group source to grow 20 periods of asymmetric structure with gradually changing Al composition (3nm) Al _y1 Ga _1-y1 N/(3nm)GaN superlattice insertion layer, as the stress control layer 105 . Among them, the Al composition y1 decreases stepwise from 1 to 0.05 with the increase of the superlattice period number, and the step change of the Al composition is realized by controlling the flow rate of TMAl (with the increase of the superlattice period number, the Al composition y1 is ₁ , 0.95 in turn , 0.9, 0.85, 0.8, 0.75, 0.7, 0.65, 0.6, 0.55, 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.05); in a hydrogen (H2) atmosphere, at 1080 ° C , injecting TMGa as a group III source, and NH ₃ as a group V source to grow a u-GaN semi-insulating layer 106 with a thickness of 2 μm. Next, at 1080°C under H ₂ atmosphere, inject TMGa and TMAl as Group III source, NH ₃ as Group V source, and SiH ₄ as n-type doping source to grow undoped 15nm AlGaN isolation layer 107, 20nm doped with Si AlGaN and 20nm undoped AlGaN barrier layer 108 .

Example 2

Use Aixtron company, tightly coupled vertical reaction chamber MOCVD growth system. During the growth process, trimethylgallium (TMGa) and trimethylaluminum (TMAl) were used as Group III sources, ammonia gas (NH ₃ ) was used as Group V sources, silane (SiH ₄ ) was used as n-type dopant sources, and dimagnesocene (Cp ₂ Mg) as the p-type dopant source, firstly heat the Si substrate 201 to 1080°C in the MOCVD reaction chamber, use TMGa and TMAl as the Group III source, and NH ₃ as the V group source in the H ₂ atmosphere, A 0.1-micron-thick AlN nucleation layer is grown; then, at 1080° C. under H ₂ atmosphere, TMAl and TMGa are introduced as Group III sources, and NH ₃ is used as V-group sources to grow a 0.5-micron thick AlGaN seed layer 202 . Aligned multilayer carbon nanotubes were grown by low-pressure chemical vapor deposition (LPCVD). During the growth process, acetylene was used as the carrier gas, and 5nm Fe was used as the catalyst. The diameter of the grown carbon nanotubes is 15 nm. Through growth and weaving, finally a continuous carbon nanotube film 203 can be formed from parallel arrays of carbon nanotubes. At 1080°C under _H2 atmosphere, inject TMGa and TMAl as Group III source, and _NH3 as Group V source to grow 1 μm GaN merged layer 204; at 1080°C under _H2 atmosphere, inject TMGa and TMAl as Group III source , NH ₃ was used as V group source to grow 20 cycles of asymmetric structure Al composition gradient (3nm)AlN/(3nm)Al _y1 Ga _1-y1 N/(3nm)GaN superlattice insertion layer, as stress Regulatory layer 205 . Among them, the Al composition y1 decreases stepwise from 1 to 0.05 with the increase of the superlattice period number, and the step change of the Al composition is realized by controlling the flow rate of TMAl (with the increase of the superlattice period number, the Al composition y1 is ₁ , 0.95 in turn , 0.9, 0.85, 0.8, 0.75, 0.7, 0.65, 0.6, 0.55, 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.05); in a hydrogen (H2) atmosphere, at 1080 ° C , feed TMGa as the III group source, and NH ₃ as the V group source to grow a u-GaN semi-insulating layer 206 with a thickness of 2 μm. Next, at 1080°C under H ₂ atmosphere, inject TMGa and TMAl as Group III source, NH ₃ as Group V source, and SiH ₄ as n-type dopant source to grow undoped 15nm AlGaN isolation layer 207, 20nm doped with Si AlGaN and 20nm undoped AlGaN barrier layer 208 .

As shown in the SEM photos of Figure 3 (b), (c), the technology of the present invention is adopted: carbon nanotubes are used as a periodic dielectric mask, the selected area epitaxy (SAG) method is adopted, and the structure of the stress regulation layer is designed to obtain a turtle-free cracked, high crystal quality AlGaN/GaN HEMT devices. AlGaN/GaN prepared by ordinary methods without using carbon nanotubes as periodic dielectric masks and without using Al _y1 Ga _1-y1 N/GaN superlattice or AlN/Al _y1 Ga _1-y1 N/GaN superlattice There are obvious cracks on the surface of the HEMT device.

The above-described embodiments are only to illustrate the technical ideas and characteristics of the present invention, and its description is more specific and detailed. Its purpose is to enable those of ordinary skill in the art to understand the content of the present invention and implement it accordingly. To limit the patent scope of the present invention, but it should not be construed as a limitation of the scope of the present invention. It should be pointed out that for those skilled in the art, some modifications and improvements can be made without departing from the concept of the present invention, that is, all changes made according to the spirit disclosed in the present invention should still include Within the patent scope of the present invention.

Claims (6)

1. the method that one kind prepares high electron mobility field-effect transistor (HEMT) on large scale Si substrates, uses trimethyl Gallium（TMGa）, trimethyl aluminium（TMAl）As group III source, ammonia（NH₃）As group V source, silane（SiH₄）As n-shaped doped source, On a si substrate, first growing AIN nucleating layer and AlGaN seed layers；It is creative on this basis to use carbon nanotubes as the cycle Property medium mask, using selective area epitaxial（SAG）Method obtains no cracking, the GaN epitaxial layer of high-crystal quality, and further makes Standby AlGaN/GaN HEMT devices；This method comprises the following steps：

Step 1, in Metal Organic Vapor epitaxial reactor, in hydrogen（H₂）Under atmosphere, on a si substrate, temperature At 1000 DEG C~1500 DEG C, TMAl is passed through as group III source, NH₃As group V source, 0.1~0.5 micron of thickness AlN nucleation is grown Layer；On this basis, at 1000 DEG C~1500 DEG C of temperature, TMAl, TMGa are passed through as group III source, NH₃As group V source, growth 0.1~1 micron of thickness AlGaN seed layer；

Step 2, using Low Pressure Chemical Vapor Deposition（LPCVD）Grow the multilayer carbon nanotube of marshalling；In growth course In, using acetylene as carrier gas, while using Fe as catalyst；Carbon nanotube diameter after growth is 15nm；Pass through growth And braiding, continuous carbon nano-tube film is finally formed by carbon nano pipe array arranged in parallel；

Step 3, in hydrogen（H₂）Under atmosphere, at 1000 DEG C~1500 DEG C, TMGa is passed through as group III source, NH₃As V races Source grows 0.1~1 micron of GaN and merges layer；

Step 4, in hydrogen（H₂）Under atmosphere, at 1000 DEG C~1500 DEG C, TMGa, TMAl are passed through as group III source, NH₃Make The Al of the Al composition gradient gradual changes of multicycle unsymmetric structure is grown for group V source_y1Ga_1-y1N/GaN superlattices insert layers, as should Power regulates and controls layer；

Step 5, in hydrogen（H₂）Under atmosphere, at 1050 DEG C~1200 DEG C, TMGa is passed through as group III source, NH₃As V races Source grows 2~4 microns of thickness μ-GaN semi-insulating layers；Then TMGa, TMAl are passed through as group III source, NH₃As group V source, SiH₄Make For 5nm~15nm AlGaN separation layers for undoping of n-shaped doped source growth, 10nm~20nm mixes the AlGaN of Si and undopes AlGaN potential barrier.

2. one kind according to claim 1 prepares high electron mobility field-effect transistor on large scale Si substrates (HEMT) method, it is characterised in that：Continuous carbon nano-tube film is formed by carbon nano pipe array periodically arranged in parallel As periodic dielectric mask；Selective area epitaxial is used on this basis（SAG）Method, using GaN in new carbon nanotubes medium The selectivity grown on mask and AlGaN seed layers is limited in GaN epitaxial layer in the region of no medium mask and grows, shape Into discrete window, the tensile stress in entire epitaxial layer is discharged.

3. one kind according to claim 1 prepares high electron mobility field-effect transistor on large scale Si substrates (HEMT) method, it is characterised in that：The stress regulation and control layer uses the Al of multicycle Al content gradually variational_y1Ga_1-y1N/GaN surpasses Lattice, wherein, Al components y₁As the increase of stress regulation and control layer number of superlattice cycles is reduced from 1 gradient to 0（0≤y1≤1)；It is super Lattice period number is 1~20.

4. one kind according to claim 1 prepares high electron mobility field-effect transistor on large scale Si substrates (HEMT) method, it is characterised in that：The stress regulation and control layer uses the Al of multicycle Al content gradually variational_y1Ga_1-y1N/GaN surpasses Lattice, the wherein thickness of superlattices well layer GaN are 1~5nm, superlattices Al_y1Ga_1-y1The thickness of N barrier layer is 1~5nm.

5. one kind according to claim 1 prepares high electron mobility field-effect transistor on large scale Si substrates (HEMT) method, it is characterised in that：The stress regulation and control layer uses the AlN/ of multicycle unsymmetric structure Al content gradually variationals Al_y1Ga_1-y1N/GaN superlattices, wherein Al components y₁With stress regulation and control layer number of superlattice cycles increase from 1 gradient reduce to 0（0≤y1≤1), number of superlattice cycles are 1~20.

6. one kind according to claim 1 prepares high electron mobility field-effect transistor on large scale Si substrates (HEMT) method, it is characterised in that：The stress regulation and control layer uses the AlN/ of multicycle unsymmetric structure Al content gradually variationals Al_y1Ga_1-y1N/GaN superlattices, the wherein thickness of superlattices well layer GaN are 1~5nm, superlattices Al_y1Ga_1-y1The thickness of N barrier layer For 1~5nm, the thickness of superlattices AlN insert layers is 1~5nm.