A gallium nitride-based bipolar junction transistor and a method of fabricating the same

Abstract

The application discloses a gallium nitride-based bipolar junction transistor and a preparation method thereof, and relates to the technical field of semiconductors; a two-dimensional electron gas layer is generated on the side close to a GaN channel layer at the interface between an AlGaN barrier layer and the GaN channel layer through piezoelectric polarization and spontaneous polarization effects; a groove for depositing and growing a P-type semiconductor layer is formed by etching from the middle of the top surface of an insulating layer to the bottom surface of the GaN channel layer; two grooves for depositing and growing an emitter and a collector are formed by etching from the top surface of an emitter insulating layer away from the end of the P-type semiconductor layer and the top surface of a collector insulating layer away from the end of the P-type semiconductor layer to the top surface of an emitter AlGaN barrier layer; a base is deposited and grown on the top surface of the P-type semiconductor layer; and the application can greatly improve the mobility of electrons in the emitter and the collector, and improve the large-current output capability, power density and high-frequency application capability of the device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, in particular to a gallium nitride-based bipolar junction transistor and a preparation method thereof. BACKGROUND

[0002] The most mature bipolar junction transistor is silicon-based bipolar junction transistor, but the highest working frequency of the silicon-based bipolar junction transistor is limited due to the low electron mobility of silicon material, in high-frequency applications, they cannot provide high gain and high speed, and the thermal conductivity of silicon material is relatively low, so the thermal noise is high. The gallium nitride-based material has high thermal conductivity, low thermal noise and better thermal stability, can work in a wider working temperature range, can realize higher saturation current density and electric field strength, and can work at higher power density. Due to the polarization effect, the AlGaN and GaN heterojunction can form a high-concentration 2DEG (two-dimensional electron gas) in the intrinsic state or low-concentration doping, which has high saturation drift speed and high mobility to ensure large current output and power density, and small parasitic impedance and capacitance to ensure high-frequency application.

[0003] In a conventional gallium nitride bipolar junction transistor (gallium nitride-based bipolar junction transistor), the gallium nitride material itself is used for current transport in the emission area and the collector area, and the AlGaN and GaN heterojunction are not used to form high-performance 2DEG. However, the electron mobility of gallium nitride material itself is not very high, so the current transmission in the emission area and the collector area needs a lot of time, which limits the large current output capability, power density and high-frequency application capability of the device. SUMMARY

[0004] The purpose of the present application is to provide a gallium nitride-based bipolar junction transistor and a preparation method thereof, which can greatly improve the electron mobility in the emission area and the collector area, and improve the large current output capability, power density and high-frequency application capability of the device.

[0005] To achieve the above purpose, the present application provides the following scheme:

[0006] A gallium nitride-based bipolar junction transistor, comprising an emitter, a base, a collector, a two-dimensional electron gas layer, a P-type semiconductor layer, a substrate, and a buffer layer, a GaN channel layer, an AlGaN barrier layer and an insulating layer grown on the substrate from bottom to top;

[0007] The two-dimensional electron gas layer is generated on the side close to the GaN channel layer at the interface between the AlGaN barrier layer and the GaN channel layer through piezoelectric polarization and spontaneous polarization effect;

[0008] a first partial groove is formed by etching down from a middle of a top surface of the insulating layer to a bottom surface of the GaN channel layer; the first partial groove is used for depositing and growing the P-type semiconductor layer; the first partial groove divides the GaN channel layer into an emission area GaN channel layer and a collector area GaN channel layer; the first partial groove divides the two-dimensional electron gas layer into an emission area two-dimensional electron gas layer and a collector area two-dimensional electron gas layer; the first partial groove divides the AlGaN barrier layer into an emission area AlGaN barrier layer and a collector area AlGaN barrier layer; and the first partial groove divides the insulating layer into an emission area insulating layer and a collector area insulating layer;

[0009] a second partial groove is formed by etching down from an end of the top surface of the emission area insulating layer away from the P-type semiconductor layer to a top surface of the emission area AlGaN barrier layer; the second partial groove is used for depositing and growing the emitter;

[0010] a third partial groove is formed by etching down from an end of the top surface of the collector area insulating layer away from the P-type semiconductor layer to a top surface of the collector area AlGaN barrier layer; the third partial groove is used for depositing and growing the collector;

[0011] the base is deposited and grown on a top surface of the P-type semiconductor layer;

[0012] a voltage is applied to the base and the collector, and electrons flow from the emitter to the collector through the emission area AlGaN barrier layer, the emission area two-dimensional electron gas layer, the P-type semiconductor layer, the collector area two-dimensional electron gas layer, and the collector area AlGaN barrier layer.

[0013] Optionally, the substrate is a silicon substrate, a sapphire substrate, a silicon carbide substrate, or a self-supporting gallium nitride substrate.

[0014] Optionally, the buffer layer is a gallium nitride layer or a superlattice structure; the gallium nitride layer is doped with iron or carbon; and the superlattice structure is an Al(Ga)N / GaN superlattice structure.

[0015] Optionally, an AlGaN or passivation layer is inserted in the buffer layer to isolate an emitter-to-collector leakage current path in the buffer layer.

[0016] Optionally, a structure for introducing a fourth electrode is arranged inside the buffer layer; the structure for introducing a fourth electrode includes a back gate; and the fourth electrode is used to adjust a working zone of the bipolar junction transistor.

[0017] Optionally, the P-type semiconductor layer is a p-type GaN layer, a p-type InGaN layer, a p-type AlGaN layer, or a NiO layer.

[0018] Optionally, the material of the insulating layer is silicon nitride, aluminum oxide or silicon oxide.

[0019] The application also provides the following solutions:

[0020] A gallium nitride-based bipolar junction transistor preparation method for preparing the above-mentioned gallium nitride-based bipolar junction transistor, the preparation method comprising:

[0021] sequentially growing a buffer layer, a GaN channel layer and an AlGaN barrier layer from bottom to top on a substrate;

[0022] generating a two-dimensional electron gas layer on the side close to the GaN channel layer at the interface between the AlGaN barrier layer and the GaN channel layer through piezoelectric polarization and spontaneous polarization effects;

[0023] depositing and growing an insulating layer on the top surface of the AlGaN barrier layer;

[0024] from the middle of the top surface of the insulating layer, etching down to the bottom surface of the GaN channel layer to form a first partial groove, and making the GaN channel layer, the two-dimensional electron gas layer, the AlGaN barrier layer and the insulating layer differentiate into an emission area GaN channel layer, a collector area GaN channel layer, an emission area two-dimensional electron gas layer, a collector area two-dimensional electron gas layer, an emission area AlGaN barrier layer, a collector area AlGaN barrier layer, an emission area insulating layer and a collector area insulating layer;

[0025] depositing and growing a p-type semiconductor layer in the first partial groove;

[0026] etching away the p-type semiconductor layer on the top surface of the emission area insulating layer and the top surface of the collector area insulating layer;

[0027] from the top surface of the emission area insulating layer, away from the end of the P-type semiconductor layer, etching down to the top surface of the emission area AlGaN barrier layer to form a second partial groove;

[0028] from the top surface of the collector area insulating layer, away from the end of the P-type semiconductor layer, etching down to the top surface of the collector area AlGaN barrier layer to form a third partial groove;

[0029] depositing and growing an emitter in the second partial groove and depositing and growing a collector in the third partial groove;

[0030] depositing and growing a base on the top surface of the P-type semiconductor layer to obtain a gallium nitride-based bipolar junction transistor.

[0031] Optionally, depositing and growing a base on the top surface of the P-type semiconductor layer to obtain a gallium nitride-based bipolar junction transistor, and the method further comprises:

[0032] The base region window is re-doped by Mg diffusion.

[0033] According to the specific embodiments of the present application, the following technical effects are disclosed:

[0034] The gallium nitride-based bipolar junction transistor and the preparation method thereof disclosed in the present application provide a novel gallium nitride-based bipolar junction transistor structure based on a two-dimensional electron gas channel, the novel gallium nitride-based bipolar junction transistor structure utilizes a high-mobility two-dimensional electron gas formed by an AlGaN / GaN heterojunction to form a channel, and the current of an emitter and a collector is limited in the two-dimensional electron gas, so that the current transmission in the original emitter region and collector region of the bipolar junction transistor is replaced, thereby greatly improving the mobility of electrons in the emitter region and the collector region, and improving the large-current output capability, power density and high-frequency application capability of the device. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0036] Figure 1 A three-dimensional structure schematic diagram of the gallium nitride-based bipolar junction transistor provided by the present application is provided.

[0037] Figure 2 A schematic diagram of cross section A of the gallium nitride-based bipolar junction transistor provided by the present application is provided.

[0038] Figure 3 A schematic diagram of cross section B of the gallium nitride-based bipolar junction transistor provided by the present application is provided.

[0039] Figure 4 A schematic diagram of cross section C of the gallium nitride-based bipolar junction transistor provided by the present application is provided.

[0040] Figure 5 A flow chart of the preparation method of the gallium nitride-based bipolar junction transistor provided by the present application is provided.

[0041] Symbol explanation:

[0042] Substrate-1, buffer layer-2, emitter region GaN channel layer-3, collector region GaN channel layer-4, P-type semiconductor layer-5, emitter region two-dimensional electron gas layer-6, collector region two-dimensional electron gas layer-7, emitter region AlGaN barrier layer-8, collector region AlGaN barrier layer-9, emitter region insulating layer-10, collector region insulating layer-11, emitter-12, collector-13, base-14. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0044] The purpose of the present application is to provide a gallium nitride-based bipolar junction transistor and a preparation method thereof, which can greatly improve the electron mobility in the emission region and the collector region, and improve the large-current output capability, power density and high-frequency application capability of the device.

[0045] In order to make the above-mentioned purposes, characteristics and advantages of the present application more apparent and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0046] The present application mainly provides a gallium nitride-based bipolar junction transistor structure, which is a novel gallium nitride-based bipolar junction transistor structure based on a two-dimensional electron gas channel. The two-dimensional electron gas generated by the AlGaN / GaN polarization effect is used for electron transport in the collector region and the emission region, so as to greatly improve the electron transport efficiency in the collector region and the emission region. Since the device uses 2DEG conduction, the AlGaN and GaN in the emission region and the collector region can be doped or intrinsic.

[0047] Embodiment 1

[0048] Figure 1 A three-dimensional structure schematic diagram of a gallium nitride-based bipolar junction transistor is provided in the embodiments of the present application. The gallium nitride-based bipolar junction transistor comprises an emitter 12, a base 14, a collector 13, a two-dimensional electron gas layer, a p-type semiconductor layer 5, a substrate 1, and a buffer layer 2, a GaN channel layer, an AlGaN barrier layer and an insulating layer grown on the substrate 1 from bottom to top.

[0049] Specifically, the substrate 1 is a silicon substrate, a sapphire substrate, a silicon carbide substrate or a self-supporting gallium nitride substrate.

[0050] The buffer layer 2 is a gallium nitride layer or a superlattice structure; wherein the gallium nitride layer is doped with iron or carbon; and the superlattice structure is an Al(Ga)N / GaN superlattice structure.

[0051] The p-type semiconductor layer 5 is a p-type GaN layer, a p-type InGaN layer, a p-type AlGaN layer or a NiO layer.

[0052] The material of the insulating layer is silicon nitride, aluminum oxide or silicon oxide.

[0053] A two-dimensional electron gas layer is generated on the side close to the GaN channel layer at the interface between the AlGaN barrier layer and the GaN channel layer by piezoelectric polarization and spontaneous polarization effects.

[0054] A first part of the groove is formed by etching down from the middle of the top surface of the insulating layer to the bottom surface of the GaN channel layer; the first part of the groove is used for depositing and growing the P-type semiconductor layer 5; the first part of the groove divides the GaN channel layer into the emitter region GaN channel layer 3 and the collector region GaN channel layer 4; the first part of the groove divides the two-dimensional electron gas layer into the emitter region two-dimensional electron gas layer 6 and the collector region two-dimensional electron gas layer 7; the first part of the groove divides the AlGaN barrier layer into the emitter region AlGaN barrier layer 8 and the collector region AlGaN barrier layer 9; and the first part of the groove divides the insulating layer into the emitter region insulating layer 10 and the collector region insulating layer 11.

[0055] A second part of the groove is formed by etching down from the top surface of the emitter region insulating layer 10 away from the end of the P-type semiconductor layer 5 to the top surface of the emitter region AlGaN barrier layer 8; the second part of the groove is used for depositing and growing the emitter 12.

[0056] A third part of the groove is formed by etching down from the top surface of the collector region insulating layer 11 away from the end of the P-type semiconductor layer 5 to the top surface of the collector region AlGaN barrier layer 9; the third part of the groove is used for depositing and growing the collector 13.

[0057] The base 14 is deposited and grown on the top surface of the P-type semiconductor layer 5.

[0058] A voltage is applied to the base 14 and the collector 13, and electrons flow from the emitter 12 through the emitter region AlGaN barrier layer 8, the emitter region two-dimensional electron gas layer 6, the P-type semiconductor layer 5, the collector region two-dimensional electron gas layer 7, the collector region AlGaN barrier layer 9, and to the collector 13.

[0059] An AlGaN or passivation layer is inserted in the buffer layer 2 to isolate the emitter-to-collector leakage current path in the buffer layer 2. A structure for introducing a fourth electrode is arranged inside the buffer layer 2; the structure for introducing the fourth electrode includes a back gate; and the fourth electrode is used to adjust the working zones of the bipolar junction transistor.

[0060] To more clearly illustrate the structure of the novel gallium nitride-based bipolar junction transistor based on a two-dimensional electron gas channel (the novel gallium nitride bipolar junction transistor based on a two-dimensional electron gas channel) provided by the present application, three cross sections A, B, and C are made on the three-dimensional structure of Figure 1 , and the cross-sectional views of Figure 2 , Figure 3 , and Figure 4 can be obtained. The cross-sectional views of Figure 2 , Figure 3 , and Figure 4 are combined.The cross-sectional view can more clearly know the novel gallium nitride bipolar junction transistor structure based on two-dimensional electron gas channel provided by the application. The novel gallium nitride bipolar junction transistor structure based on two-dimensional electron gas channel provided by the application is further specifically described below by taking the p-type semiconductor layer as the p-type GaN layer as an example:

[0061] The novel gallium nitride bipolar junction transistor structure based on two-dimensional electron gas channel provided by the application includes the substrate 1, the buffer layer 2, the emission area GaN channel layer 3, the collector area GaN channel layer 4, the p-type GaN layer 5, the emission area 2DEG (emission area two-dimensional electron gas layer) 6, the collector area 2DEG (collector area two-dimensional electron gas layer) 7, the emission area AlGaN barrier layer 8, the collector area AlGaN barrier layer 9, the emission area insulating layer 10, the collector area insulating layer 11, the emitter 12, the collector 13 and the base 14 from bottom to top.

[0062] The substrate 1 is located at the bottom of the whole structure and serves as a support, and can be but is not limited to a silicon (Silicon) substrate, a sapphire (Sapphire) substrate, a silicon carbide (SiC) substrate or a self-supporting gallium nitride substrate.

[0063] The buffer layer 2 is located above the substrate 1, and can use but is not limited to a gallium nitride layer doped with iron (Fe) or carbon (C) or an Al(Ga)N / GaN superlattice structure, and can be but is not limited to inserting AlGaN or a passivation layer into the buffer layer 2 to isolate the emitter-to-collector leakage current path in the buffer layer, and can be but is not limited to arranging a structure similar to a back gate inside the buffer layer 2 to introduce a fourth electrode to adjust the working zones of the bipolar junction transistor.

[0064] The emission area GaN channel layer 3 and the collector area GaN channel layer 4 are located above the buffer layer 2.

[0065] The p-type GaN layer 5 is located above the buffer layer 2, and can be but is not limited to being embedded inside the buffer layer 2 or extending above the emission area insulating layer 10 and the collector area insulating layer 11, and can use but is not limited to using (InGaN, AlGaN, etc.) p-type InGaN, p-type AlGaN, NiO and other materials or material combinations exhibiting p-type semiconductor properties to replace the p-type GaN.

[0066] The emission area AlGaN barrier layer 8 and the collector area AlGaN barrier layer 9 are located above the emission area GaN channel layer 3 and the collector area GaN channel layer 4, and generate the emission area 2DEG 6 and the collector area 2DEG 7 respectively on the side close to the channel layer at the interface (boundary) between the two and the corresponding channel layer through piezoelectric polarization and spontaneous polarization effects.

[0067] The emitter 12 and the collector 13 are located at the two ends of the device at the top. The base 14 is located above the p-type GaN layer 5.

[0068] The emission region insulating layer 10 is located on the emission region AlGaN barrier layer 8, and the collector region insulating layer 11 is located on the collector region AlGaN barrier layer 9, both of which can use, but are not limited to, silicon nitride (Si3N4), aluminum oxide (Al2O3), or silicon oxide (SiO2) as the insulating layer material.

[0069] In the present application, the emission region 2DEG 6 and the p-type GaN layer 5 form the emission junction in the bipolar junction transistor structure, and the collector region 2DEG 7 and the p-type GaN layer 5 form the collector junction in the bipolar junction transistor structure. The p-type GaN layer 5 is the base region in the bipolar junction transistor. In the present application, a multi-layer AlGaN / GaN structure can be constructed to form a multi-layer 2DEG. The present application is described by an npn-type bipolar junction transistor, but it is also possible to form a pnp-type bipolar junction transistor by using the two-dimensional hole gas for hole transport in the collector region and the emission region.

[0070] Compared with the prior art, the present application proposes a new type of gallium nitride bipolar junction transistor structure based on a two-dimensional electron gas channel, which uses the high-mobility two-dimensional electron gas formed by the AlGaN / GaN heterojunction to form a channel, and limits the current of the emitter and the collector in the two-dimensional electron gas, instead of the original emission region and collector region in the bipolar junction transistor for current transmission, thereby greatly improving the mobility of electrons in the emission region and the collector region, and improving the large-current output capability, power density, and high-frequency application capability of the device.

[0071] In the present application, electrons do not necessarily enter the collector region from the contact between the collector region 2DEG and the p-type GaN layer, but the electrons entering the emission region from other interfaces will also be pulled into the 2DEG channel due to the AlGaN / GaN polarization effect, that is, most of the electron transport in the emission region and the collector region in the present application will be transmitted through the 2DEG channel.

[0072] Embodiment 2

[0073] The present application provides a preparation method of a gallium nitride-based bipolar junction transistor, as shown in the figure, the preparation method is used for preparing the gallium nitride-based bipolar junction transistor in embodiment 1, and the preparation method comprises the following steps: Figure 5

[0074] Step 100: growing a buffer layer, a GaN channel layer, and an AlGaN barrier layer in sequence from bottom to top on a substrate.

[0075] Step 200: generating a two-dimensional electron gas layer on the side close to the GaN channel layer at the interface between the AlGaN barrier layer and the GaN channel layer through piezoelectric polarization and spontaneous polarization effects.

[0076] ​In practical applications, an epitaxial wafer with formed substrate, buffer layer, GaN channel layer, 2DEG layer, and AlGaN barrier layer can be selected, and then mesa isolation is performed, and then surface treatment (acid treatment: HCl, H2SO4+H2O2, BOE) is performed on the device after the mesa isolation is completed.

[0077] Step 300: depositing and growing an insulating layer on the top surface of the AlGaN barrier layer.

[0078] The deposition of the insulating layer can be performed after surface treatment is performed on the device after the mesa isolation is completed.

[0079] Step 400: etching from the middle of the top surface of the insulating layer to the bottom surface of the GaN channel layer to form a first part of the groove, and dividing the GaN channel layer, two-dimensional electron gas layer, AlGaN barrier layer, and insulating layer into an emission area GaN channel layer, a collector area GaN channel layer, an emission area two-dimensional electron gas layer, a collector area two-dimensional electron gas layer, an emission area AlGaN barrier layer, a collector area AlGaN barrier layer, an emission area insulating layer, and a collector area insulating layer.

[0080] By etching the GaN channel layer, 2DEG layer, AlGaN barrier layer, and insulating layer, the p-type semiconductor layer deposition area (first part of the groove) is exposed, and the GaN channel layer, 2DEG layer, AlGaN barrier layer, and passivation layer (insulating layer) are divided into an emission area GaN channel layer, a collector area GaN channel layer, an emission area 2DEG, a collector area 2DEG, an emission area AlGaN barrier layer, a collector area AlGaN barrier layer, an emission area insulating layer, and a collector area insulating layer.

[0081] Step 500: depositing and growing a p-type semiconductor layer in the first part of the groove.

[0082] The p-type semiconductor layer is deposited by MOCVD.

[0083] Step 600: etching away the p-type semiconductor layer on the top surface of the emission area insulating layer and the top surface of the collector area insulating layer.

[0084] The p-type semiconductor layer and other unnecessary p-type semiconductor layers outside the p-type semiconductor layer need to be etched away.

[0085] Step 700: etching from the top surface of the emission area insulating layer away from the end of the p-type semiconductor layer to the top surface of the emission area AlGaN barrier layer to form a second part of the groove.

[0086] Step 800: etching from the top surface of the collector area insulating layer away from the end of the p-type semiconductor layer to the top surface of the collector area AlGaN barrier layer to form a third part of the groove.

[0087] By etching the emitter region insulating layer 10 and the collector region insulating layer 11, the contact areas of the emitter 12 and the collector 13, i.e. the second part of the groove and the third part of the groove, are exposed.

[0088] Step 900: depositing and growing an emitter in the second part of the groove and depositing and growing a collector in the third part of the groove.

[0089] By using an electron beam evaporation, a magnetron sputtering or a thermal evaporation process, an ohmic contact metal (e.g. Ti / Al / Ni / Au) is evaporated on the emitter and collector area windows, and an emitter and a collector are formed by high-temperature annealing.

[0090] Step 1000: depositing and growing a base on the top surface of the P-type semiconductor layer to obtain a gallium nitride-based bipolar junction transistor.

[0091] By using an electron beam evaporation, a magnetron sputtering or a thermal evaporation process, an ohmic contact metal (e.g. Ni / Au) is evaporated on the base area window, and a base is formed by high-temperature annealing.

[0092] Specifically, depositing and growing a base on the top surface of the P-type semiconductor layer to obtain a gallium nitride-based bipolar junction transistor further comprises the following steps before the step:

[0093] The base area window is heavily doped by Mg diffusion.

[0094] The steps of the preparation method of the gallium nitride-based bipolar junction transistor provided by the application will be described below by taking a p-type semiconductor layer as a p-type GaN layer as an example:

[0095] Step 1: select an epitaxial wafer having formed a substrate, a buffer layer, a GaN channel layer, a 2DEG layer and an AlGaN barrier layer.

[0096] Step 2: mesa isolation.

[0097] Step 3: perform surface treatment (acid treatment: HCl, H2SO4+H2O2, BOE) on the device after the mesa isolation.

[0098] Step 4: deposit an insulating layer.

[0099] Step 5: etch the GaN channel layer, the 2DEG layer, the AlGaN barrier layer and the insulating layer to expose the deposition area of the p-type GaN layer and to divide the GaN channel layer, the 2DEG layer, the AlGaN barrier layer and the passivation layer into an emitter region GaN channel layer, a collector region GaN channel layer, an emitter region 2DEG, a collector region 2DEG, an emitter region AlGaN barrier layer, a collector region AlGaN barrier layer, an emitter region insulating layer and a collector region insulating layer.

[0100] Step 6: deposit a p-type GaN layer by MOCVD.

[0101] Step 7: etching the p-type GaN layer outside other unnecessary p-type GaN layer.

[0102] Step 8: etching the emission area insulating layer, the collector area insulating layer, and exposing the contact area of the emitter and the collector.

[0103] Step 9: using electron beam evaporation, magnetron sputtering or thermal evaporation process to evaporate ohmic contact metal (such as Ti / Al / Ni / Au) on the emitter and collector area window, and high temperature annealing to form the emitter and the collector.

[0104] Step 10: re-doping by Mg diffusion in the base area window.

[0105] Step 11: using electron beam evaporation, magnetron sputtering or thermal evaporation process to evaporate ohmic contact metal (such as Ni / Au) on the base area window, and high temperature annealing to form the base.

[0106] The preparation method of the gallium nitride-based bipolar junction transistor provided by the application can prepare the novel gallium nitride bipolar junction transistor structure based on two-dimensional electron gas channel. The novel gallium nitride bipolar junction transistor structure based on two-dimensional electron gas channel uses the two-dimensional electron gas (2DEG) generated by the AlGaN / GaN polarization effect to perform electron transport in the collector area and the emitter area, which can greatly improve the electron transport efficiency in the collector area and the emitter area.

[0107] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between various embodiments can be referred to each other.

[0108] The principles and implementation manners of the application are described by using specific examples in the present application, and the above description of the embodiments is only used to help understand the method of the application and its core idea; meanwhile, for the person skilled in the art, according to the idea of the application, the specific implementation manner and application range will be changed. In conclusion, the content of the specification should not be understood as the limitation of the application.

Claims

1. A gallium nitride-based bipolar junction transistor, characterized in that, The gallium nitride-based bipolar junction transistor includes: an emitter, a base, a collector, a two-dimensional electron gas layer, a P-type semiconductor layer, a substrate, and a buffer layer, a GaN channel layer, an AlGaN barrier layer, and an insulating layer grown sequentially from bottom to top on the substrate. At the interface between the AlGaN barrier layer and the GaN channel layer, a two-dimensional electron gas layer is generated on the side near the GaN channel layer through piezoelectric polarization and spontaneous polarization effects; the two-dimensional electron gas generated by the AlGaN / GaN polarization effect is used for electron transport in the collector and emitter regions. From the center of the top surface of the insulating layer, etching downwards to the bottom surface of the GaN channel layer forms a first partial groove; the first partial groove is used to deposit and grow the P-type semiconductor layer; the first partial groove divides the GaN channel layer into an emitter GaN channel layer and a collector GaN channel layer; the first partial groove divides the two-dimensional electron gas layer into an emitter two-dimensional electron gas layer and a collector two-dimensional electron gas layer; the first partial groove divides the AlGaN barrier layer into an emitter AlGaN barrier layer and a collector AlGaN barrier layer; the first partial groove divides the insulating layer into an emitter insulating layer and a collector insulating layer; From the top surface of the emitter insulating layer away from the end of the P-type semiconductor layer, etching is performed downwards to the top surface of the emitter AlGaN barrier layer to form a second groove; the second groove is used to deposit and grow the emitter. From the top surface of the collector region insulating layer away from the end of the P-type semiconductor layer, etching is performed downwards to the top surface of the collector region AlGaN barrier layer to form a third groove; the third groove is used to deposit and grow the collector electrode. The base electrode is deposited and grown on the top surface of the P-type semiconductor layer; When a voltage is applied to the base and the collector, electrons flow from the emitter through the emitter region AlGaN barrier layer, the emitter region two-dimensional electron gas layer, the p-type semiconductor layer, the collector region two-dimensional electron gas layer, and the collector region AlGaN barrier layer to the collector. The p-type semiconductor layer is a p-type GaN layer, a p-type InGaN layer, a p-type AlGaN layer, or a NiO layer. The high-mobility two-dimensional electron gas formed by the AlGaN / GaN heterojunction is used to form a channel, confining the current of the emitter and collector within the two-dimensional electron gas, thus replacing the emitter and collector regions in the original bipolar junction transistor for current transmission.

2. The gallium nitride-based bipolar junction transistor according to claim 1, characterized in that, The substrate is a silicon substrate, a sapphire substrate, a silicon carbide substrate, or a self-supporting gallium nitride substrate.

3. The gallium nitride-based bipolar junction transistor according to claim 1, characterized in that, The buffer layer is a gallium nitride layer or a superlattice structure; the gallium nitride layer is doped with iron or carbon; the superlattice structure is an Al(Ga)N / GaN superlattice structure.

4. The gallium nitride-based bipolar junction transistor according to claim 1, characterized in that, The buffer layer is incorporating AlGaN or a passivation layer to isolate the emitter-collector leakage current path within the buffer layer.

5. The gallium nitride-based bipolar junction transistor according to claim 1, characterized in that, The buffer layer is provided with a structure for introducing a fourth electrode; the structure for introducing the fourth electrode includes a back gate; the fourth electrode is used to adjust the working partition of the bipolar junction transistor.

6. The gallium nitride-based bipolar junction transistor according to claim 1, characterized in that, The insulating layer is made of silicon nitride, aluminum oxide, or silicon oxide.

7. A method for fabricating a gallium nitride-based bipolar junction transistor, characterized in that, The preparation method is used to prepare the gallium nitride-based bipolar junction transistor according to any one of claims 1-6, and the preparation method includes: A buffer layer, a GaN channel layer, and an AlGaN barrier layer are grown sequentially from bottom to top on the substrate. A two-dimensional electron gas layer is generated at the interface between the AlGaN barrier layer and the GaN channel layer through piezoelectric polarization and spontaneous polarization effects on the side closer to the GaN channel layer. An insulating layer is deposited and grown on the top surface of the AlGaN barrier layer; From the middle of the top surface of the insulating layer, etching is performed downwards to the bottom surface of the GaN channel layer to form a first partial groove, thereby differentiating the GaN channel layer, the two-dimensional electron gas layer, the AlGaN barrier layer, and the insulating layer into an emitter GaN channel layer, a collector GaN channel layer, an emitter two-dimensional electron gas layer, a collector two-dimensional electron gas layer, an emitter AlGaN barrier layer, a collector AlGaN barrier layer, an emitter insulating layer, and a collector insulating layer. A p-type semiconductor layer is deposited and grown within the first portion of the groove; The p-type semiconductor layer on the top surface of the emitter region insulating layer and the top surface of the collector region insulating layer is etched away; From the top surface of the emitter insulating layer away from the end of the P-type semiconductor layer, the etching extends downwards to the top surface of the emitter AlGaN barrier layer to form a second groove. From the top surface of the collector region insulating layer away from the end of the P-type semiconductor layer, the etching extends downward to the top surface of the collector region AlGaN barrier layer to form a third groove. An emitter is deposited and grown in the second portion of the groove, and a collector is deposited and grown in the third portion of the groove; A base electrode is deposited and grown on the top surface of the P-type semiconductor layer to obtain a gallium nitride-based bipolar junction transistor.

8. The method for fabricating a gallium nitride-based bipolar junction transistor according to claim 7, characterized in that, A base electrode is deposited and grown on the top surface of the P-type semiconductor layer to obtain a gallium nitride-based bipolar junction transistor, which further includes: Heavy doping is achieved through Mg diffusion in the base region window.

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