Gallium nitride device and electronic equipment

Abstract

According to the gallium nitride device and the electronic equipment provided by the invention, the back barrier layer with non-uniform thickness in the direction from the source electrode to the drain electrode is arranged in the channel layer below the P-GaN layer, the thickness close to the source electrode is larger, and the thickness close to the drain electrode is smaller, so that the region with large thickness can improve the confinement of 2DEG, and the reliability of the device is improved. The channel resistance can be reduced by the area with small thickness, so that the problem that the channel resistance is relatively large or the short channel effect is relatively obvious due to the fact that only the back barrier layer with single thickness is adopted in the traditional design can be avoided by adjusting the thickness of the back barrier layer below the P-GaN layer; according to the invention, the compromise relationship between the short channel effect and the conduction characteristic can be effectively balanced.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of semiconductor technology, and in particular to a gallium nitride device and an electronic device. BACKGROUND

[0002] With the global energy structure accelerating towards clean and intelligent direction, the energy efficiency and power density demand of power electronic systems presents exponential growth. The next generation of electronic systems represented by 5G communication, new energy vehicles and data center power supply have higher requirements for the performance of low-voltage (5-20V) power devices: high-frequency switching, low-conduction loss and high-integration under limited voltage margin. The traditional silicon-based MOSFET device is limited by the material physical properties, and there is a "silicon limit" relationship between its on-resistance Ron,sp and breakdown voltage BV, which is difficult to meet the high-energy conversion demand in low-voltage scenarios. Gallium nitride (GaN) high electron mobility transistor (HEMT) provides a good solution to break through the performance bottleneck of silicon-based devices, with its wide band gap, high two-dimensional electron gas (2DEG) concentration and excellent electron mobility.

[0003] However, as the feature size of GaN HEMT devices continues to shrink, the threshold voltage drift and drain-induced barrier lowering (DIBL) caused by short channel effects (SCE) seriously restrict the practical process of low-voltage GaN HEMT, especially in low-voltage (15-40V) application scenarios. The device needs to achieve high frequency, low power consumption and high reliability under sub-micron channel length, but the physical law of the traditional long channel model gradually fails at this scale. This is because the gate edge electric field significantly weakens the gate control ability due to the distortion of two-dimensional / three-dimensional electrostatic potential distribution. Short channel effects not only cause threshold voltage drift, drain-induced barrier lowering (DIBL) and other static parameter degradation, but also cause hot carrier injection (HCI), current collapse and other dynamic reliability problems.

[0004] Therefore, in GaN-based HEMT devices, to solve the problems of threshold voltage drift and drain-induced barrier lowering caused by short channel effects, how to improve the confinement of 2DEG in the channel under the gate is an important optimization direction of GaN HEMT devices. SUMMARY

[0005] Embodiments of the present disclosure provide a gallium nitride device and an electronic device for improving the confinement of 2DEG in the channel under the gate. The specific scheme is as follows: In one aspect, the present disclosure provides a gallium nitride device, comprising: a substrate, a nucleation layer, a buffer layer, a channel layer and a barrier layer which are sequentially stacked in an epitaxial direction; and comprising: a source electrode and a drain electrode located on both sides of the barrier layer, the source electrode and the drain electrode are electrically connected with the channel layer, respectively; a P-GaN layer located on a side of the barrier layer away from the substrate and between the source and the drain; a gate located on a side of the P-GaN layer away from the substrate; a back barrier layer located in the buffer layer, or in the channel layer, or between the buffer layer and the channel layer; the back barrier layer comprises at least two regions with different thicknesses in a direction from the source to the drain, the direction from the source to the drain is perpendicular to the epitaxial direction, a region of the back barrier layer close to the source has a thickness greater than a region of the back barrier layer close to the drain, and a footprint of the P-GaN layer on the substrate covers footprints of the regions of the back barrier layer with different thicknesses on the substrate.

[0006] In some embodiments, in the gallium nitride device provided by the embodiments of the present disclosure, the back barrier layer comprises a first region and a second region connected to each other, the first region is close to the source, and the second region is close to the drain, and the thickness of the first region is greater than the thickness of the second region.

[0007] In some embodiments, in the gallium nitride device provided by the embodiments of the present disclosure, the thickness of each position of the first region is the same, or the thickness of the first region gradually decreases in a direction from the source to the drain.

[0008] In some embodiments, in the gallium nitride device provided by the embodiments of the present disclosure, the thickness of each position of the second region is the same, or the thickness of the second region gradually decreases in a direction from the source to the drain.

[0009] In some embodiments, in the gallium nitride device provided by the embodiments of the present disclosure, further comprising: a third region located between the first region and the second region, the thickness of the first region is greater than the thickness of the third region, and the thickness of the third region is greater than the thickness of the second region.

[0010] In some embodiments, in the gallium nitride device provided by the embodiments of the present disclosure, the thickness of each position of the third region is the same, or the thickness of the third region gradually decreases in a direction from the source to the drain.

[0011] In some embodiments, in the gallium nitride device provided by the embodiments of the present disclosure, a footprint of the P-GaN layer on the substrate covers footprints of at least two adjacent regions of the first region, the third region and the second region on the substrate.

[0012] In some embodiments, in the gallium nitride device provided by the embodiments of the present disclosure, each of the regions with gradually reduced thickness is curved away from the surface of the substrate.

[0013] In some embodiments, in the gallium nitride device provided by the embodiments of the present disclosure, the bottom surface of the back barrier layer facing the substrate is in contact with the buffer layer, the back barrier layer is embedded in the channel layer, the thickness of the back barrier layer is less than the thickness of the channel layer, and the material of the back barrier layer is In x Al y Ga (1-x-y) N, wherein x>0 and y>0.

[0014] In another aspect, the embodiments of the present disclosure also provide an electronic device comprising the gallium nitride device provided by the embodiments of the present disclosure.

[0015] The beneficial effects of the present disclosure are as follows: The gallium nitride device and the electronic device provided by the embodiments of the present disclosure can improve the confinement of 2DEG by setting the back barrier layer with non-uniform thickness in the direction from the source electrode to the drain electrode in the channel layer below the P-GaN layer, and the thickness is greater near the source electrode and smaller near the drain electrode. Therefore, the present disclosure can effectively balance the trade-off between short channel effect and conduction characteristics by adjusting the thickness of the back barrier layer below the P-GaN layer, thereby avoiding the problems of large channel resistance or obvious short channel effect caused by using only a single thickness of the back barrier layer in the traditional design. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 FIG. 1 shows a structural schematic diagram of a gallium nitride device provided by the embodiments of the present disclosure; Figure 2 FIG. 2 shows another structural schematic diagram of a gallium nitride device provided by the embodiments of the present disclosure; Figure 3 FIG. 3 shows still another structural schematic diagram of a gallium nitride device provided by the embodiments of the present disclosure; Figure 4 FIG. 4 shows still another structural schematic diagram of a gallium nitride device provided by the embodiments of the present disclosure; Figure 5 FIG. 5 shows a structural schematic diagram of a gallium nitride device in a preparation process; Figure 1 Figure 6 FIG. 7 shows another structural schematic diagram of a gallium nitride device in a preparation process; Figure 1 FIG. 8 shows still another structural schematic diagram of a gallium nitride device in a preparation process; Figure 7 Figure 1 FIG. 9 shows still another structural schematic diagram of a gallium nitride device in a preparation process; ​​Figure 8 FIG. 7 is another schematic diagram of a structure of a gallium nitride device during fabrication, according to some embodiments of the present disclosure; Figure 1 FIG. 8 is another schematic diagram of a structure of a gallium nitride device during fabrication, according to some embodiments of the present disclosure. Figure 9 FIG. 9 is another schematic diagram of a structure of a gallium nitride device during fabrication, according to some embodiments of the present disclosure. Figure 1 FIG. 10 is another schematic diagram of a structure of a gallium nitride device during fabrication, according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0017] For the purpose of making the objects, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings of the embodiments of the present disclosure. It should be noted that, in the drawings, the thicknesses of layers, films, panels, regions, and the like are exaggerated for clarity. In the present disclosure, the exemplary embodiments are described with reference to cross-sectional views that are schematic illustrations of idealized embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and / or tolerances, are to be expected. Thus, embodiments described in the present disclosure are not to be construed as limited to the precise shapes as illustrated but are to include deviations in shapes that result, for example, from manufacturing. For example, an area illustrated or described as flat can typically have rough and / or nonlinear features; an illustrated sharp angle can be rounded, etc. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region that is to be constructed and are not reflective of true scale, but are merely to illustrate the relationships of the regions to each other as understood by one of ordinary skill in the art. Like numbers refer to like or similar elements throughout. To maintain brevity, the description of known functions and structures incorporated herein can be omitted.

[0018] Unless otherwise defined, technical terms or scientific terms used herein shall have the same meaning as commonly understood by one of ordinary skill in the art to which this present disclosure belongs. The terms "first", "second", and similar terms do not denote any order, quantity, or importance, but are used to distinguish one element from another, and the terms "comprises", "comprising", "includes", "including" and the like can be used herein. Such terms are like a "contain" or like a "contain", and are not to be construed as excluding other elements or steps therein. The terms "connected", "coupled", and similar terms are not limited to a physical or mechanical connection or coupling, but also include an electrical connection or coupling, whether direct or indirect. The terms "inner", "outer", "upper", "lower", and the like are used only to indicate relative positions, and when the absolute positions of the described objects are changed, the relative positions can also be changed accordingly.

[0019] In the following description, when an element or layer is referred to as "on" or "connected to" another element or layer, the element or layer may be directly on or directly connected to the other element or layer, or there may be intermediate elements or intermediate layers. When an element or layer is referred to as "located on one side of" another element or layer, the element or layer may be directly on or directly connected to the other element or layer, or there may be intermediate elements or intermediate layers. However, when an element or layer is referred to as "directly on" or "directly connected to" another element or layer, no intermediate elements or intermediate layers are present. The term "and / or" includes any and all combinations of one or more of the related listed items.

[0020] Currently, in traditional GaN HEMT devices, introducing an AlGaN back barrier layer beneath the channel can effectively improve the energy band near the channel, thereby enhancing the confinement of the 2DEG in the under-gate channel and strengthening the gate's control over the channel. For example, when the drain voltage is high, the back barrier layer not only prevents the 2DEG from extending downwards, thus blocking current flow in the region beneath the channel, but the raised energy band also mitigates the drain-induced barrier reduction effect.

[0021] However, traditional back barrier layer structures also lead to the following two problems: 1. The elevated energy band results in a decrease in 2DEG concentration, leading to an increase in drift region and channel resistance, which degrades the device's on-resistance and is detrimental to the device's on-state characteristics. 2. Typically, to enhance its influence on the heterojunction channel, the back barrier layer is placed closer to the channel, which degrades the device's dynamic characteristics.

[0022] To address the two problems mentioned above caused by traditional back barrier layer structures, this disclosure provides a gallium nitride device, such as... Figure 1 As shown, it includes: a substrate 100, a nucleation layer 109, a buffer layer 101, a channel layer 102, and a barrier layer 103 sequentially stacked along the epitaxial direction X; the channel layer 102 and the barrier layer 103 form a heterojunction, and a high-concentration, high-mobility two-dimensional electron gas (2DEG) can be induced on the side of the channel layer 102 near the barrier layer 103; the dashed lines in the channel layer 102 represent the 2DEG. This gallium nitride device also includes: Source 105 and drain 106 are located on both sides of barrier layer 103. Source 105 and drain 106 are electrically connected to channel layer 102 respectively. Source 105 and drain 106 form ohmic contacts with two-dimensional electron gas respectively. The P-GaN layer 104 is located on the side of the barrier layer 103 away from the substrate 100, and is located between the source 105 and the drain 106. Gate 107 is located on the side of P-GaN layer 104 away from substrate 100; The back barrier layer 108 is located in the buffer layer 101, or in the channel layer 102, or between the buffer layer 101 and the channel layer 102; in the direction Y from the source electrode 105 to the drain electrode 106, which is perpendicular to the epitaxial direction X, the back barrier layer 108 includes at least two regions with different thicknesses, the region near the source electrode 105 has a greater thickness than the region near the drain electrode 106, and the orthogonal projection of the P-GaN layer 104 on the substrate 100 covers the orthogonal projection of the different thickness regions of the back barrier layer 108 on the substrate 100.

[0023] The gallium nitride device provided by the embodiments of the present disclosure can improve the confinement of 2DEG by setting the back barrier layer with uneven thickness in the direction from the source electrode to the drain electrode in the channel layer below the P-GaN layer, and the thickness near the source electrode is greater and the thickness near the drain electrode is smaller, so that the region with greater thickness can reduce the channel resistance, and the region with smaller thickness can reduce the channel resistance, so that the present disclosure can effectively balance the compromise between the short channel effect and the conduction characteristics by adjusting the thickness of the back barrier layer below the P-GaN layer.

[0024] In some embodiments, the substrate 100 can be a Si, SiC, GaN, sapphire, etc. substrate, and the present disclosure does not limit this.

[0025] In some embodiments, in the gallium nitride device provided by the embodiments of the present disclosure, as shown in Figure 1 The material of the nucleation layer 109 can be one or a combination of AlN, GaN, and AlGaN.

[0026] In some embodiments, in the gallium nitride device provided by the embodiments of the present disclosure, as shown in Figure 1 The material of the buffer layer 101 can be Al x Ga 1-x N, where 0≤x≤1, the buffer layer 101 can be a gradually changing Al x Ga 1-x N multilayer combination, or a superlattice structure with different x values alternately; the thickness of the buffer layer 101 can be 0-8 μm, and it can be understood that 0 μm is not included.

[0027] In some embodiments, the material of the channel layer 102 can be GaN, the thickness of the channel layer 102 can be 10-500 nm, and the C doping concentration of the channel layer 102 can be <1×10 17 cm -3 .

[0028] In some embodiments, the material of the barrier layer 103 can be a group III nitride layer, for example, In x Al y Ga (1-x-y) N, where x≥0, y>0, for example, the material of the barrier layer 103 can be one or a combination of AlN and AlGaN; the band gap of the barrier layer 103 is greater than the band gap of the channel layer 102; the thickness of the barrier layer 103 can be 5-30 nm.

[0029] In some embodiments, the P-GaN layer 104 can be Mg-doped GaN, and the doping concentration can be 1×10 17 ~1×10 20 cm -3 The thickness of the P-GaN layer 104 can be 30-200 nm.

[0030] In some embodiments, the material of the source electrode 105 includes but is not limited to one or a combination of Ti, TiN, Al, Ni, Pt, Pd, Si, and Au; the material of the drain electrode 106 includes but is not limited to one or a combination of Ti, TiN, Al, Ni, Pt, Pd, Si, and Au; and the material of the gate electrode 107 includes but is not limited to one or a combination of Ti, TiN, Al, Ni, Pt, Pd, Si, and Au.

[0031] In some embodiments, in the above-mentioned gallium nitride device provided by the embodiments of the present disclosure, the bottom surface of the back barrier layer 108 facing the substrate 100 is in contact with the buffer layer 101, and the back barrier layer 108 is embedded in the channel layer 102, so that the back barrier layer 108 is formed by epitaxial growth and etching on the buffer layer 101, and then the channel layer 102 and the barrier layer 103 are formed by secondary epitaxy, i.e., the back barrier layer 108 is located between the buffer layer 101 and the channel layer 102, the thickness of the back barrier layer 108 is less than the thickness of the channel layer 102, and the material of the back barrier layer 108 can be a group III nitride layer, for example, In x Al y Ga (1-x-y) N, where x≥0, y>0, for example, the material of the barrier layer 103 can be one or a combination of AlN and AlGaN; the band gap of the barrier layer 103 is greater than the band gap of the channel layer 102.

[0032] It should be noted that the back barrier layer 108 in the embodiments of the present disclosure is not limited to being epitaxially grown and etched after the buffer layer 101. The buffer layer 101 of a certain thickness can be first epitaxially grown, the back barrier layer 108 can be epitaxially grown and etched on the buffer layer 101, and then the buffer layer 101 of a certain thickness, the channel layer 102, the barrier layer 103 and the like can be continuously epitaxially grown, that is, the back barrier layer 108 is located in the buffer layer 101. The channel layer 102 of a certain thickness can be first epitaxially grown on the buffer layer 101, then the back barrier layer 108 can be epitaxially grown and etched on the channel layer 102, and then the channel layer 102 of a certain thickness, the barrier layer 103 and the like can be continuously epitaxially grown, that is, the back barrier layer 108 is located in the channel layer 102.

[0033] In some embodiments, in the above-mentioned gallium nitride device provided by the embodiments of the present disclosure, as shown in Figure 1 , the back barrier layer 108 includes a connected first region 1081 and a second region 1082, the first region 1081 is close to the source electrode 105, the second region 1082 is close to the drain electrode 106, the thickness of the first region 1081 is greater than the thickness of the second region 1082, for example, the thickness of each position of the first region 1081 is the same, the thickness of each position of the second region 1082 is the same, that is, the back barrier layer 108 is a stepped structure with two flat surfaces, and the orthographic projection of the P-GaN layer 104 on the substrate 100 covers at least part of the orthographic projection of the first region 1081 and at least part of the orthographic projection of the second region 1082 on the substrate 100, so that the back barrier layer 108 with uneven thickness is arranged in the channel layer 102 below the P-GaN layer 104, and the thickness close to the source electrode 105 is greater, and the thickness close to the drain electrode 106 is smaller.

[0034] In some embodiments, in the above-mentioned gallium nitride device provided by the embodiments of the present disclosure, as shown in Figure 1 , the distance between the gate electrode 107 and the source electrode 105 can be less than the distance between the gate electrode 107 and the drain electrode 106, and the distance between the first region 1081 and the source electrode 105 can be less than the distance between the second region 1082 and the drain electrode 106.

[0035] In some embodiments, in the above-mentioned gallium nitride device provided by the embodiments of the present disclosure, as shown in Figure 2 , the distance between the gate electrode 107 and the source electrode 105 can be less than the distance between the gate electrode 107 and the drain electrode 106, and the distance between the first region 1081 and the source electrode 105 can be less than the distance between the second region 1082 and the drain electrode 106. Figure 2 In some embodiments, in the above-mentioned gallium nitride device provided by the embodiments of the present disclosure, as shown in Figure 2 , the distance between the gate electrode 107 and the source electrode 105 can be less than the distance between the gate electrode 107 and the drain electrode 106, and the distance between the first region 1081 and the source electrode 105 can be less than the distance between the second region 1082 and the drain electrode 106. Figure 1 The difference between the gallium nitride device provided by the embodiments of the present disclosure and Figure 2 , in the direction from the source electrode 105 to the drain electrode 106, the second region 1082 of the back barrier layer 108 can extend to the vicinity of the drain electrode 106, for example, the distance between the first region 1081 and the source electrode 105 can be greater than the distance between the second region 1082 and the drain electrode 106, Figure 2 may have the same structure asFigure 1 The same technical effects can be achieved.

[0036] In some embodiments, in the gallium nitride device provided by the embodiments of the present disclosure, the structures of the first region 1081 and the second region 1082 are not limited to Figure 1 The water flat surface in the above-mentioned gallium nitride device provided by the embodiments of the present disclosure can also be that the thickness of each position of the first region 1081 is the same, and the thickness of the second region 1082 gradually decreases, for example, as shown in Figure 3 Figure 3 The structure of another gallium nitride device provided by the embodiments of the present disclosure is Figure 3 The difference between the gallium nitride device provided by the embodiments of the present disclosure and the gallium nitride device provided by the prior art is that Figure 1 In the gallium nitride device provided by the embodiments of the present disclosure, along the direction from the source electrode 105 to the drain electrode 106, the thickness of the second region 1082 gradually decreases, for example, the surface of the second region 1082 away from the surface of the substrate 100 is a curved surface, that is, the thickness change of the second region 1082 is a curvature change, Figure 3 The same technical effects can be achieved. Figure 3 Figure 1 In some embodiments, in the gallium nitride device provided by the embodiments of the present disclosure, when the thickness of the first region 1081 gradually decreases, the surface of the first region 1081 away from the surface of the substrate 100 can be a curved surface, that is, the thickness change of the first region 1081 is a curvature change.

[0037] In some embodiments, in the gallium nitride device provided by the embodiments of the present disclosure, the structures of the first region 1081 and the second region 1082 can also be that along the direction from the source electrode 105 to the drain electrode 106, the thickness of the first region 1081 can gradually decrease, and the thickness of the second region 1082 can also gradually decrease; or the thickness of the first region 1081 gradually decreases, and the thickness of each position of the second region 1082 is the same.

[0038] In some embodiments, in the gallium nitride device provided by the embodiments of the present disclosure, as shown in

[0039] The structure of another gallium nitride device provided by the embodiments of the present disclosure is Figure 4 The difference between the gallium nitride device provided by the embodiments of the present disclosure and the gallium nitride device provided by the prior art is that Figure 4 Figure 4 Figure 1 Figure 4 ​​​​​The third region 1083 is located between the first region 1081 and the second region 1082, the thickness of the first region 1081 is greater than the thickness of the third region 1083, and the thickness of the third region 1083 is greater than the thickness of the second region 1082, that is, in the direction from the source electrode 105 to the drain electrode 106, the thickness of the first region 1081, the thickness of the third region 1083, and the thickness of the second region 1082 gradually decrease. Specifically, the thickness of each position of the first region 1081 is the same, the thickness of each position of the third region 1083 is the same, and the thickness of each position of the second region 1082 is the same, that is, the back barrier layer 108 has a multi-step water platform in the thickness change.

[0040] In some embodiments, in the above-mentioned gallium nitride device provided by the embodiments of the present disclosure, as shown in Figure 4 The orthogonal projection of the P-GaN layer 104 on the substrate 100 covers the orthogonal projection of at least two adjacent regions of the first region 1081, the third region 1083, and the second region 1082 on the substrate 100, and the embodiments of the present disclosure take the orthogonal projection of the P-GaN layer 104 on the substrate 100 covering the orthogonal projection of the first region 1081, the third region 1083, and part of the second region 1082 on the substrate 100 as an example, so that the back barrier layer 108 with uneven thickness is arranged in the channel layer 102 below the P-GaN layer 104, and the thickness near the source electrode 105 is greater, and the thickness near the drain electrode 106 is smaller, Figure 4 may have the same technical effects as Figure 1 .

[0041] In some embodiments, as shown in Figure 4 The orthogonal projection of the P-GaN layer 104 on the substrate 100 can only cover the orthogonal projection of the first region 1081 and the third region 1083 on the substrate 100, and the orthogonal projection of the P-GaN layer 104 on the substrate 100 can also cover the orthogonal projection of the third region 1083 and the second region 1082 on the substrate 100.

[0042] In some embodiments, in the above-mentioned gallium nitride device provided by the embodiments of the present disclosure, Figure 4 The structure of the first region 1081, the third region 1083, and the second region 1082 can also be that, in the direction from the source electrode 105 to the drain electrode 106, the thickness of the first region 1081, the thickness of the third region 1083, and the thickness of the second region 1082 gradually decrease; can also be that the thickness of each position of one of the first region 1081, the third region 1083, and the second region 1082 is the same, and the thickness of the other two gradually decreases; can also be that the thickness of each position of two of the first region 1081, the third region 1083, and the second region 1082 is the same, and the thickness of the other gradually decreases.

[0043] In some embodiments, in the gallium nitride device provided in the present disclosure, when the thickness of the third region 1083 gradually decreases, the surface of the third region 1083 away from the substrate 100 can be curved, that is, the change in thickness of the third region 1083 is a change in curvature.

[0044] In some embodiments of the gallium nitride device provided in this disclosure, the back barrier layer 108, along the direction from the source 105 to the drain 106, is not limited to including... Figure 1 The two horizontal platform surfaces shown and Figure 4 The three water level platforms shown can also include more water level platforms, as long as a non-uniform back barrier layer 108 is provided in the channel layer 102 below the P-GaN layer 104, with a greater thickness near the source 105 and a smaller thickness near the drain 106.

[0045] To better understand the gallium nitride devices provided in the embodiments of this disclosure, this disclosure uses... Figure 1 Taking the gallium nitride device shown as an example, the fabrication process of the gallium nitride device will be explained in detail.

[0046] In some embodiments, Figure 1 The fabrication process of the gallium nitride device shown may specifically include the following steps: (1) such as Figure 5 As shown, a nucleation layer 109, a buffer layer 101, and a back barrier layer 108 are epitaxially grown on one side of a substrate 100 using methods such as MOCVD.

[0047] (2) For example Figure 6 As shown, the back barrier layer 108 corresponding to the area outside the gate region is etched, and only the back barrier layer 108 under the gate near the source end is left unetched, forming etching steps of different thicknesses.

[0048] (3) such as Figure 7 As shown, the back barrier layer 108 is further partially etched so that except for the back barrier layer 108 under the gate, the remaining positions are completely etched to form a back barrier layer 108 with a stepped structure including two horizontal platform surfaces.

[0049] (4) such as Figure 8 As shown, a secondary epitaxial layer 102 is formed and polished with CMP to make the surface of the secondary epitaxial layer 102 smooth.

[0050] (5) such as Figure 9As shown, the barrier layer 103 and the P-GaN layer 104 are continuously formed by epitaxy, the gate 107 is formed by depositing gate metal on the side of the P-GaN layer 104 away from the substrate 100, and the P-GaN layer 104 outside the gate 107 is etched away with the gate 107 as a mask. Then, ohmic metal is deposited on both sides of the barrier layer 103 to form the source 105 and the drain 106, which form ohmic contacts with the two-dimensional electron gas (2DEG) at the heterojunction interface between the channel layer 102 and the barrier layer 103.

[0051] Therefore, the gallium nitride device shown in the figure is formed by the above steps (1)-(5). Figure 1

[0052] Based on the same inventive concept, the present disclosure provides an electronic device comprising the above gallium nitride device provided by the present disclosure. Since the principle of solving problems of the electronic device is similar to that of the above gallium nitride device, the implementation of the electronic device provided by the present disclosure can be referred to the implementation of the above gallium nitride device provided by the present disclosure, and the repeated parts will not be described here.

[0053] In some embodiments, the above electronic device provided by the present disclosure can include but is not limited to: radio frequency amplifier, frequency mixer, radar, satellite, power supply, automobile electronics, energy-saving lamp, household appliance, etc. Of course, the electronic device provided by the present disclosure can include other structures in addition to the gallium nitride device, for example, when the electronic device is a radar, it further includes: transmitter, antenna, receiver, etc. structure; when the electronic device is a frequency mixer, it further includes: input port and output port, etc. structure.

[0054] Although the preferred embodiments of the present disclosure have been described, those skilled in the art can make further changes and modifications to the embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including all changes and modifications falling within the scope of the present disclosure.

[0055] Obviously, those skilled in the art can make various modifications and variations to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalent technologies, the present disclosure also intends to include these modifications and variations.​

Claims

1. A gallium nitride device, characterized by, The gallium nitride device comprises: a substrate, a nucleation layer, a buffer layer, a channel layer and a barrier layer which are sequentially stacked in an epitaxial direction; and a source electrode and a drain electrode which are located on two sides of the barrier layer and are electrically connected to the channel layer respectively; a P-GaN layer which is located on a side of the barrier layer away from the substrate and between the source electrode and the drain electrode; a gate electrode which is located on a side of the P-GaN layer away from the substrate; a back barrier layer which is located in the buffer layer, or in the channel layer, or between the buffer layer and the channel layer; the back barrier layer comprises at least two regions with different thicknesses in a direction from the source electrode to the drain electrode, the direction from the source electrode to the drain electrode is perpendicular to the epitaxial direction, a region of the back barrier layer close to the source electrode has a greater thickness than a region of the back barrier layer close to the drain electrode, and a projection of the P-GaN layer on the substrate covers projections of the regions of the back barrier layer with different thicknesses on the substrate.

2. The gallium nitride device of claim 1, wherein, The back barrier layer comprises a first region and a second region which are connected, the first region is close to the source electrode, the second region is close to the drain electrode, and the first region has a greater thickness than the second region.

3. The gallium nitride device of claim 2, wherein, The thickness of the first region is the same at different positions, or the thickness of the first region gradually decreases in the direction from the source electrode to the drain electrode.

4. The gallium nitride device of claim 2, wherein, The thickness of the second region is the same at different positions, or the thickness of the second region gradually decreases in the direction from the source electrode to the drain electrode.

5. The gallium nitride device of any one of claims 2-4, wherein, The gallium nitride device further comprises: a third region which is located between the first region and the second region, the first region has a greater thickness than the third region, and the third region has a greater thickness than the second region.

6. The gallium nitride device of claim 5, wherein, The thickness of the third region is the same at different positions, or the thickness of the third region gradually decreases in the direction from the source electrode to the drain electrode.

7. The gallium nitride device of claim 5, wherein the gallium nitride device is a light emitting diode. A projection of the P-GaN layer on the substrate covers projections of at least two adjacent regions of the first region, the third region and the second region on the substrate.

8. The gallium nitride device of any of claims 3-4, 6, wherein, The surface of each region with gradually decreasing thickness away from the substrate is a curved surface.

9. The gallium nitride device of claim 1 wherein, The bottom surface of the back barrier layer facing the substrate is in contact with the buffer layer, the back barrier layer is embedded in the channel layer, the thickness of the back barrier layer is less than the thickness of the channel layer, and the material of the back barrier layer is In x Al y Ga (1-x-y) N, wherein x≥0, y>0.

10. An electronic device, comprising: The gallium nitride device comprises the gallium nitride device according to any one of claims 1-9.

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