Enhanced GaN power device

Abstract

The embodiment of the invention provides an enhanced GaN power device, and the device comprises a substrate which comprises a channel layer and a barrier layer which form an electron gas channel; the source electrode and the drain electrode are arranged at an interval along the first direction and are electrically connected through the electron gas channel; the first depletion layer is arranged on the barrier layer and located between the source electrode and the drain electrode, the first depletion layer comprises a first depletion body and a second depletion body, the second depletion body comprises a depletion monomer, and the depletion monomer comprises a first end connected with the first depletion body and a second end spaced from the drain electrode; a non-depletable region and a depletable region which are arranged along a second direction are defined by the depletion monomer in the electron gas channel, and the second direction is intersected with the first direction; and the first grid electrode is arranged on the first depletion body and is in ohmic contact with the first depletion body. According to the embodiment of the invention, the electric field distribution of the device in the off-state drain electrode high-pressure stress can be optimized so as to improve the breakdown voltage, and the trap effect in the device can be effectively inhibited so as to optimize the dynamic resistance degradation problem of the device.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to an enhanced GaN power device. Background Art

[0002] GaN power devices have the advantages of low on-resistance, low parasitic capacitance and high switching rate. After years of development, GaN power devices have been widely used in consumer electronics. However, the performance of GaN power devices is still far from the physical theoretical limit of its materials. In order to further optimize the performance of GaN devices, the device structure design is optimized to reduce the square resistance of the device or increase the breakdown voltage of the device. One of the commonly used device structures is the super junction structure.

[0003] The superjunction power devices in the related technologies all require a normally-on two-dimensional electron gas channel, which is inconsistent with the enhancement technology required by the power devices and will affect the reliability of the devices and power systems.

[0004] Therefore, a new power device is urgently needed. Summary of the invention

[0005] In view of the problems existing in the background technology, the embodiment of the present application provides an enhanced GaN power device, which can not only optimize the electric field distribution of the device when it is in the off state and the drain high voltage stress to increase the breakdown voltage, but also effectively suppress the trap effect in the device to optimize the dynamic resistance degradation problem of the device.

[0006] An embodiment of the present application provides an enhancement-mode GaN power device, which includes: a substrate, including a channel layer and a barrier layer that form an electron gas channel; a source and a drain, which are spaced apart along a first direction and electrically connected via the electron gas channel; a first depletion layer, which is disposed on the barrier layer and located between the source and the drain, the first depletion layer including a first depletion body and a second depletion body, the second depletion body including a depletion monomer, the depletion monomer including a first end connected to the first depletion body and a second end spaced apart from the drain, and the depletion monomer defines the electron gas channel into a non-depletable region and a depletable region arranged along a second direction, the second direction intersecting with the first direction; a first gate, which is disposed on the first depletion body and in ohmic contact with the first depletion body.

[0007] According to an embodiment of the present application, an absolute value of a difference between a depletion voltage of the depletion cell and a depletion voltage of the depletable region is not greater than a preset value.

[0008] According to any of the aforementioned embodiments of the present application, the depletion voltage of the first end is greater than the depletion voltage of the second end.

[0009] According to any of the foregoing embodiments of the present application, the width of the first end is greater than the width of the second end.

[0010] According to any of the aforementioned embodiments of the present application, along the direction from the first end to the second end, the depletion voltage of the depletion monomer shows a gradually decreasing trend.

[0011] According to any of the aforementioned embodiments of the present application, along the direction from the first end to the second end, the width of the depletion monomer shows a gradually decreasing trend.

[0012] According to any of the aforementioned embodiments of the present application, the depletion voltage of the first end is less than the depletion voltage of the second end.

[0013] According to any of the foregoing embodiments of the present application, the width of the first end is smaller than the width of the second end.

[0014] According to any of the aforementioned embodiments of the present application, along the direction from the first end to the second end, the depletion voltage of the depletion monomer presents a gradually increasing trend.

[0015] According to any of the aforementioned embodiments of the present application, along the direction from the first end to the second end, the width of the depletion monomer shows a gradually increasing trend.

[0016] According to any of the aforementioned embodiments of the present application, the depletion voltage of the first end is the same as the depletion voltage of the second end.

[0017] According to any of the foregoing embodiments of the present application, the width of the first end is equal to the width of the second end.

[0018] According to any of the aforementioned embodiments of the present application, along the direction from the first end to the second end, the variation coefficient of the depletion voltage of the depletion cell is 0.

[0019] According to any of the aforementioned embodiments of the present application, the depletion monomers are arranged with equal width along the direction from the first end to the second end.

[0020] According to any of the aforementioned embodiments of the present application, at least two depletion monomers are provided, and the at least two depletion monomers are arranged at equal intervals along the second direction.

[0021] According to any of the aforementioned embodiments of the present application, the first depletion layer further includes a third depletion body, the third depletion body is disposed between the first depletion body and the second depletion body, and the first depletion body and the second depletion body are connected via the third depletion body.

[0022] According to any of the foregoing embodiments of the present application, the enhanced GaN power device further includes a second depletion layer and a second gate, wherein the second depletion layer is disposed on the barrier layer and between the source and the first depletion layer, and the second gate is disposed on a side of the second depletion layer away from the barrier layer.

[0023] According to any of the aforementioned embodiments of the present application, the first gate and the source are spaced apart from each other; or, the first gate and the source are short-circuited.

[0024] According to any of the aforementioned embodiments of the present application, the base body further includes a buffer layer disposed on a side of the channel layer away from the barrier layer, a transition layer disposed on a side of the buffer layer away from the channel layer, and a substrate disposed on a side of the transition layer away from the buffer layer.

[0025] In an embodiment of the present application, when the enhanced GaN power device is in the off state, under low drain high voltage, the holes provided by the depletion monomer and the two-dimensional electron gas in the depletable region can be rapidly depleted laterally, so that the depletion region can be rapidly expanded. As the drain high voltage stress further increases, an electric field similar to a rectangular distribution will be formed in the depletion region from the drain to the first gate. From the perspective of semiconductor physics, due to the formation of a rectangular electric field distribution, the integral value of the electric field in the depletion region is higher, so the breakdown voltage of the enhanced GaN power device is higher. In addition, when the enhanced GaN power device is turned on, since the depletion monomer is connected to the first depletion body, the first gate and the first depletion body can provide movable holes for the depletion monomer, and the movable holes can effectively shield the surface layer traps of the barrier layer; at the same time, since the first gate is prepared on the first depletion body by ohmic contact, when the first gate is applied with a positive bias, the first depletion body and the second depletion body can both achieve a hole injection effect, and the injected holes can recombine with the two-dimensional electron gas under the barrier layer to emit light, and can also accelerate the recovery of the surface layer traps. That is, by setting the depletion monomer, not only can the electric field distribution of the device be optimized when the drain is under high voltage stress in the off state to increase the breakdown voltage, but the trap effect in the device can also be effectively suppressed to optimize the dynamic resistance degradation problem of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. The drawings are not drawn according to the true scale.

[0027] Figure 1 A schematic diagram of the structure of an enhanced GaN power device provided in one embodiment of the present application;

[0028] Figure 2 for Figure 1 A cross-sectional view of the enhanced GaN power device along the AA direction;

[0029] Figure 3 for Figure 2 Schematic diagram of the structure of the electron gas channel in the enhancement mode GaN power device shown;

[0030] Figure 4 A schematic structural diagram of an enhanced GaN power device provided in another embodiment of the present application;

[0031] Figure 5A schematic structural diagram of an enhanced GaN power device provided in yet another embodiment of the present application;

[0032] Figure 6 A schematic structural diagram of an enhanced GaN power device provided in yet another embodiment of the present application;

[0033] Figure 7 A schematic structural diagram of an enhanced GaN power device provided in yet another embodiment of the present application;

[0034] Figure 8 A schematic structural diagram of an enhanced GaN power device provided in yet another embodiment of the present application.

[0035] Description of labels:

[0036] 1. Base; 1A. Electron gas channel; 1B. Non-depletable region; 1C. Depletable region; 1D. Interruption; 11. Channel layer; 13. Barrier layer; 15. Buffer layer; 17. Transition layer; 19. Substrate;

[0037] 2. Source;

[0038] 3. Drain;

[0039] 4, first depletion layer; 41, first depletion body; 43, second depletion body; 431, depletion monomer; 433, first end; 435, second end; 45, third depletion body;

[0040] 5. The first gate;

[0041] 6. Second depletion layer;

[0042] 7. Second grid;

[0043] X, first direction; Y, second direction. DETAILED DESCRIPTION

[0044] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and Examples. It should be understood that the specific embodiments described herein are only configured to explain the present application and are not configured to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0045] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish an entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only include those elements, but also include other elements not clearly listed, or also include elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements limited by the sentence "include..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. In addition, in this article, the meaning of "multiple" is more than two, and "above" and "below" include the number.

[0046] GaN power devices have the advantages of low on-resistance, low parasitic capacitance and high switching rate. After years of development, GaN power devices have been widely used in consumer electronics. However, the performance of GaN power devices is still far from the physical theoretical limit of its material. In order to further optimize the performance of GaN devices, the device structure design is optimized to reduce the square resistance of the device or increase the breakdown voltage of the device. One of the commonly used device structures is the superjunction structure. The superjunction power devices in the related technology require a normally-on two-dimensional electron gas channel, which is inconsistent with the enhanced technology required by the power device and will affect the reliability of the device and the power system. For example,

[0047] Related technology 1 (A. Nakajima, Y. Sumida, M. H. Dhyani, H. Kawai, and E. M. S. Narayanan, "GaN-Based Super Heterojunction Field Effect Transistors Using the Polarization Junction Concept," IEEE Electron Device Lett., vol. 32, no. 4, pp. 542-544, 2011, DOI: 10.1109 / LED.2011.2105242.) discloses a GaN super junction power device prepared by spontaneous polarization effect, which uses electrons and holes formed by spontaneous polarization effect to form a super junction. When the device is turned off, the paired electron and hole pairs can be quickly depleted vertically, so that the depletion region is quickly expanded, thereby improving the breakdown voltage of the device;

[0048] Related technology 2 (S. Han, J. Song, S. H. Oo, Z. Ma, R. M. Lavelle, D. W. Snyder, J. M. Redwing, T. N. Jackson, and R. Chu, "Experimental Demonstration of Charge-Balanced GaN Super-Heterojunction Schottky Barrier Diode Capable of 2.8k V Switching," IEEE Electron Device Lett., vol. 41, no. 12, pp. 1758-1761, Dec. 2020, DOI: 10.1109 / LED.2020.3029619.) discloses a super junction structure that forms a super junction by acceptor doping in p-GaN and donor doping on the barrier layer.

[0049] In addition, in the current preparation process of enhanced GaN power devices, there are surface layer traps and buffer layer traps in the barrier layer. When the device undergoes drain high voltage stress, the surface layer traps and buffer layer traps will capture electrons to form deep energy level negative charge centers. After the device is turned on, these deep energy level negative charge centers will partially or completely deplete the two-dimensional electron gas, resulting in a decrease in the two-dimensional electron gas concentration, thereby increasing the dynamic on-resistance of the device, that is, the dynamic resistance degradation problem.

[0050] In order to solve the above technical problems, an embodiment of the present application provides an enhancement-mode GaN power device, which can optimize the electric field distribution of the enhancement-mode GaN power device when it is in the off-state drain high voltage stress by setting a depletion monomer to further improve the breakdown voltage and suppress the dynamic resistance degradation problem of the enhancement-mode GaN power device.

[0051] Optionally, the shape of the enhanced GaN power device may be square, rectangular, circular, irregular, etc., which is not limited in the present application.

[0052] Optionally, the enhancement-mode GaN power device may be a diode or a triode.

[0053] To better understand this application, Figures 1 to 8 The enhanced GaN power device in the embodiment of the present application is described in detail.

[0054] Please refer to Figures 1 to 3 , Figure 1 A schematic diagram of the structure of an enhanced GaN power device provided in one embodiment of the present application; Figure 2 for Figure 1A cross-sectional view of the enhanced GaN power device along the AA direction; Figure 3 for Figure 2 Schematic diagram of the structure of the electron gas channel in the enhancement mode GaN power device shown.

[0055] like Figures 1 to 3 As shown, the enhanced GaN power device includes a substrate 1, a source 2, a drain 3, a first depletion layer 4 and a first gate 5. The substrate 1 includes a channel layer 11 and a barrier layer 13 forming an electron gas channel 1A, the source 2 and the drain 3 are arranged at intervals along a first direction X and are electrically connected through the electron gas channel 1A, the first depletion layer 4 is arranged on the barrier layer 13 and is located between the source 2 and the drain 3, the first depletion layer 4 includes a first depletion body 41 and a second depletion body 43, the second depletion body 43 includes a depletion monomer 431, the depletion monomer 431 includes a first end 433 connected to the first depletion body 41 and a second end 435 arranged at intervals from the drain 3, and the depletion monomer 431 defines the electron gas channel 1A into a non-depletable region 1B and a depletable region 1C arranged along a second direction Y, the second direction Y intersects with the first direction X, and the first gate 5 is arranged on the first depletion body 41 and is in ohmic contact with the first depletion body 41.

[0056] Optionally, the material of the channel layer 11 includes at least one of gallium nitride, aluminum gallium nitride, aluminum nitride, indium nitride and aluminum indium gallium nitride.

[0057] Optionally, the material of the barrier layer 13 includes at least one of aluminum gallium nitride, aluminum nitride, indium nitride and aluminum indium gallium nitride.

[0058] Optionally, the bandgap width of the channel layer 11 is smaller than the bandgap width of the barrier layer 13, so that the channel layer 11 provides an electron gas channel 1A for the two-dimensional electron gas, and the barrier layer 13 forms a high-concentration, high-mobility two-dimensional electron gas in the electron gas channel 1A through spontaneous polarization and piezoelectric polarization effects.

[0059] like Figure 2 As shown, optionally, when there is no bias voltage on the first gate 5 or the gate-source voltage is 0V, there is no two-dimensional electron gas below the barrier layer 13 with the first depletion layer 4 and an interruption 1D is formed, that is, there is no two-dimensional electron gas in the region corresponding to the electron gas channel 1A and the first depletion layer 4, while there is initially a two-dimensional electron gas below the barrier layer 13 without the first depletion layer 4, that is, there is initially a two-dimensional electron gas in the part of the electron gas channel 1A except the interruption 1D, so that the enhancement-mode GaN power device is an enhancement-mode device; when a positive bias voltage is applied to the first gate 5, two-dimensional electron gas is excited below the barrier layer 13 with the first depletion layer 4, that is, the interruption 1D is supplemented by the two-dimensional electron gas to make the electron gas channel 1A conductive, so that the enhancement-mode GaN power device is turned on.

[0060] like Figure 2As shown, optionally, the positive projections of the interrupt 1D and the first depletion layer 4 on the barrier layer 13 coincide or substantially coincide; the positive bias voltage applied to the first gate 5 is not less than the threshold voltage of the first gate 5 to turn on the enhancement mode GaN power device.

[0061] Optionally, the first depletion body 41 has a low resistance characteristic so that the first depletion body 41 has holes formed by ionization.

[0062] Optionally, the first depletion body 41 is a P-type doped semiconductor.

[0063] Optionally, the P-type doping in the first depletion body 41 is activated, has good conductive properties, and has holes formed by doping ionization.

[0064] Optionally, the semiconductor material of the first depletion body 41 includes at least one of gallium nitride, aluminum gallium nitride, aluminum nitride, and indium nitride.

[0065] Optionally, the second depletion body 43 has a low resistance characteristic so that the second depletion body 43 has holes formed by ionization.

[0066] Optionally, the second depletion body 43 is a P-type doped semiconductor.

[0067] Optionally, the P-type doping in the second depletion body 43 is activated, has good conductive properties, and has holes formed by doping ionization.

[0068] Optionally, the semiconductor material of the second depletion body 43 includes at least one of gallium nitride, aluminum gallium nitride, aluminum nitride, and indium nitride.

[0069] Optionally, there are multiple methods for preparing the first depletion layer 4. In some optional embodiments, the first depletion layer 4 can be prepared by the following method:

[0070] Growing a layer of P-type doped semiconductor on the barrier layer 13;

[0071] The first depletion body 41 and the second depletion body 43 are formed by etching respectively.

[0072] In some other embodiments, the first depletion layer 4 may also be prepared by the following method:

[0073] A first depletion body 41 is prepared on the barrier layer 13;

[0074] A layer of P-type doped semiconductor is grown on the barrier layer 13 , and a second depletion body 43 is formed by photolithography and selective etching.

[0075] like Figure 3As shown, optionally, the non-depletable region 1B is a region without an electron gas channel 1A of the two-dimensional electron gas below the barrier layer 13 provided with the depletion monomer 431 , that is, the interruption 1D includes the non-depletable region 1B.

[0076] Optionally, the orthographic projections of the non-depletable region 1B and the depletion monomer 431 on the barrier layer 13 coincide with or substantially coincide with each other.

[0077] like Figure 2 and Figure 3 As shown, optionally, the depletable region 1C is a region where the electron gas channel 1A with the two-dimensional electron gas initially exists below the barrier layer 13 where no depletion monomer 431 is provided between the first depletion body 41 and the drain 3 .

[0078] like Figure 2 and Figure 3 As shown, optionally, the depletable region 1C and the non-depletable region 1B constitute an electron gas channel 1A region between the first depletion body 41 and the drain 3 .

[0079] In the embodiment of the present application, when the enhanced GaN power device is in the off-state drain high voltage stress, under low drain high voltage, the holes provided by the depletion monomer 431 and the two-dimensional electron gas in the depletable region 1C can be rapidly depleted laterally, so that the depletion region expands rapidly. As the high voltage stress of the drain 3 further increases, an electric field similar to a rectangular distribution will be formed in the depletion region from the drain 3 to the first gate 5. From the perspective of semiconductor physics, due to the formation of a rectangular electric field distribution, the integral value of the electric field in the depletion region is higher, and therefore, the breakdown voltage of the enhanced GaN power device is higher. In addition, when the enhanced GaN power device is turned on, since the depletion monomer 431 is connected to the first depletion body 41, the first gate 5 and the first depletion body 41 can provide movable holes for the depletion monomer 431, and the movable holes can effectively shield the surface layer traps of the barrier layer 13; at the same time, since the first gate 5 adopts ohmic contact to prepare the first depletion body 41, when the first gate 5 is applied with a positive bias, the first depletion body 41 and the second depletion body 43 can both achieve a hole injection effect, and the injected holes can recombine with the two-dimensional electron gas under the barrier layer 13 to emit light, and can also be restored by adding surface layer traps. That is, by setting the depletion monomer 431, not only can the electric field distribution of the device be optimized when the drain high voltage stress is in the off state to increase the breakdown voltage, but also the trap effect in the device can be effectively suppressed to optimize the dynamic resistance degradation problem of the device.

[0080] Optionally, the average breakdown electric field of the enhanced GaN power device approaches the breakdown electric field limit of the material of the enhanced GaN power device, wherein the average breakdown electric field is the ratio of the breakdown voltage to the gate-drain spacing.

[0081] Optionally, the breakdown electric field limit of the material of the enhancement mode GaN power device is 3.3 MV / cm.

[0082] For example, the average breakdown electric field of the enhancement-mode GaN power device may be 3.29 MV / cm, 3.28 MV / cm, 3.27 MV / cm, 3.26 MV / cm, or 3.27 MV / cm, etc.

[0083] Optionally, the thickness of the first depletion body 41 and the thickness of the second depletion body 43 can be set in a variety of ways. Figure 1 and Figure 2 As shown, in some optional embodiments, the thickness of the first depletion body 41 is greater than the thickness of the second depletion body 43. The direction from the channel layer 11 to the barrier layer 13 is the thickness direction.

[0084] like Figures 1 to 3 As shown, optionally, there are multiple ways to set the first direction X and the second direction Y, and the first direction X and the second direction Y can be arranged to intersect at any preset angle. In some optional embodiments, the angle between the first direction X and the second direction Y is 90 degrees. The angle between the first direction X and the second direction Y is 90 degrees, which is more conducive to improving the breakdown voltage.

[0085] like Figure 1 and Figure 2 As shown, in some embodiments, the source electrode 2 and / or the drain electrode 3 are disposed on the surface of the barrier layer 13 facing away from the channel layer 11 .

[0086] In some other embodiments, the source 2 and / or the drain 3 may also be configured to be partially inserted into the barrier layer 13 .

[0087] like Figure 1 and Figure 2 As shown, in some embodiments, the first depletion layer 4 is disposed on the surface of the barrier layer 13 facing away from the channel layer 11 .

[0088] In some other embodiments, the first depletion layer 4 may also be configured to be partially inserted into the barrier layer 13 .

[0089] Optionally, when the enhancement-mode GaN power device is in the off state, the depletion monomer 431 and the depletable region 1C may be depleted at the same time or may not be depleted at the same time.

[0090] In some optional embodiments, simultaneous depletion of the depletion monomer 431 and the depletable region 1C is more conducive to optimizing the electric field distribution, thereby making the breakdown voltage of the device higher.

[0091] In some optional embodiments, when the depletion monomer 431 and the depletable region 1C are not depleted at the same time, the depletion monomer 431 and the depletable region 1C can assist each other in depletion, which can also achieve optimization of the electric field distribution, and the smaller the difference between the depletion monomer 431 and the depletable region 1C, the more conducive to the optimization performance of the electric field distribution.

[0092] In some embodiments, the absolute value of the difference between the depletion voltage of the depletion monomer 431 and the depletion voltage of the depletable region 1C is not greater than a preset value. Thus, the difference between the depletion voltage of the depletion monomer 431 and the depletable region 1C is controlled within a certain range. The preset value can be set according to the demand for the breakdown voltage of the device, and the embodiments of the present application do not specifically limit this.

[0093] In some embodiments, the depletion voltage of the first end 433 is greater than the depletion voltage of the second end 435. Since the depletion monomer 431 and the depletable region 1C are laterally depleted when the enhanced GaN power device is in the off state, and the depletion voltage of the first end 433 is greater than the depletion voltage of the second end 435, the two-dimensional electron gas of the depletable region 1C is quickly depleted near the first gate 5, and the depletion monomer 431 is quickly depleted near the drain 3, thereby achieving a smaller parasitic capacitance, which has the potential to play a role in higher frequency applications.

[0094] Optionally, the depletion voltage of the depletion monomer 431 is equal to the depletion rate of the depletion monomer 431*the width of the depletion monomer 431. The depletion voltage of the depletion monomer 431 can be controlled by adjusting the width of the depletion monomer 431; the depletion rate of the depletion monomer 431 can be controlled by adjusting the thickness and doping concentration of the depletion monomer 431.

[0095] like Figure 1 As shown, in some optional embodiments, the width of the first end 433 is greater than the width of the second end 435. Compared with controlling the depletion voltage at different positions of the depletion monomer 431 by adjusting the depletion rate at different positions of the depletion monomer 431, controlling the depletion voltage at different positions of the depletion monomer 431 by adjusting the width at different positions of the depletion monomer 431 is not only simpler to implement, but also more precise.

[0096] like Figure 1 As shown, in some embodiments, the depletion voltage of the depletion monomer 431 shows a gradually decreasing trend along the direction from the first end 433 to the second end 435. This can prevent the depletion voltage of the depletion monomer 431 from decreasing sharply at a certain position along the direction from the first end 433 to the second end 435, thereby affecting the electric field distribution.

[0097] like Figure 1As shown, in some embodiments, the width of the depletion monomer 431 shows a gradually decreasing trend along the direction from the first end 433 to the second end 435. That is, the width of the depletion monomer 431 is smaller at a position closer to the drain 3, and correspondingly, the width of the depletable region 1C is larger at a position closer to the drain 3. Compared with controlling the change trend of the depletion voltage of the depletion monomer 431 by adjusting the depletion rate change of the depletion monomer 431, controlling the change trend of the depletion voltage of the depletion monomer 431 by adjusting the width change of the depletion monomer 431 is not only simpler to implement, but also more precise to control.

[0098] Optionally, the gradually decreasing variation trend may be a linear variation trend, that is, the depletion monomer 431 is in a trapezoidal shape.

[0099] See also Figure 4 , Figure 4 A schematic structural diagram of an enhanced GaN power device provided in another embodiment of the present application.

[0100] like Figure 4 As shown, in some embodiments, the depletion voltage of the first end 433 is less than the depletion voltage of the second end 435. Since the second end 435 is spaced apart from the drain 3, the depletable region 1C has less two-dimensional electron gas at a position close to the first gate 5 than the depletable region 1C has two-dimensional electron gas at a position close to the drain 3. Therefore, the depletion voltage of the first end 433 is less than the depletion voltage of the second end 435, which makes it easier to achieve charge balance at a position close to the first gate 5 and a position close to the drain 3 or to ensure that the depletion monomer 431 and the two-dimensional electron gas are depleted at the same time, thereby achieving a more optimized electric field distribution to improve the breakdown voltage of the device.

[0101] In some embodiments, the width of the first end 433 is smaller than the width of the second end 435 .

[0102] In some embodiments, the depletion voltage of the depletion cell 431 gradually increases along the direction from the first end 433 to the second end 435, so as to avoid the depletion voltage of the depletion cell 431 increasing sharply at a certain position along the direction from the first end 433 to the second end 435 and affecting the electric field distribution.

[0103] In some embodiments, the width of the depletion monomer 431 shows a gradually increasing trend along the direction from the first end 433 to the second end 435. That is, the width of the depletion monomer 431 increases as it is closer to the drain 3, and correspondingly, the width of the depletable region 1C decreases as it is closer to the drain 3.

[0104] Optionally, the gradually increasing variation trend may be a linear variation trend, that is, the depletion monomer 431 is in a trapezoidal shape.

[0105] See also Figure 5 , Figure 5 A schematic structural diagram of an enhanced GaN power device provided in yet another embodiment of the present application.

[0106] like Figure 5 As shown, in some embodiments, the depletion voltage of the first terminal 433 is the same as the depletion voltage of the second terminal 435. Such a setting can take into account the performance requirements of the device for parasitic capacitance and breakdown voltage.

[0107] In some embodiments, the width of the first end 433 is equal to the width of the second end 435 .

[0108] In some embodiments, the coefficient of variation of the depletion voltage of the depletion cell 431 along the direction from the first end 433 to the second end 435 is zero.

[0109] In some embodiments, the depletion monomers 431 are arranged with the same width along the direction from the first end 433 to the second end 435. That is, the depletion monomers 431 are rectangular.

[0110] See also Figure 6 , Figure 6 A schematic structural diagram of an enhanced GaN power device provided in yet another embodiment of the present application.

[0111] like Figure 6 As shown, in some embodiments, the first depletion layer 4 further includes a third depletion body 45, which is disposed between the first depletion body 41 and the second depletion body 43, and the first depletion body 41 and the second depletion body 43 are connected via the third depletion body 45. By providing the third depletion body 45, the electric field peak value of the first gate 5 region can be reduced when the drain high voltage stress is turned off, and the electric field concentration effect on one side of the first gate 5 can be avoided, thereby improving the reliability and breakdown characteristics of the device. In addition, the inventors have found that since the third depletion body 45 needs to be depleted, if the first gate 5 is connected to the third depletion body 45, this will cause the depletion region to expand along the third depletion body 45 to the first gate 5, and a high electric field will appear, thereby deteriorating the withstand voltage characteristics of the device.

[0112] Optionally, the third depletion body 45 is a P-type doped semiconductor.

[0113] Optionally, the semiconductor material of the third depletion body 45 includes at least one of gallium nitride, aluminum gallium nitride, aluminum nitride, and indium nitride.

[0114] Optionally, there are multiple ways to set the thickness of the third depletion body 45. In some optional embodiments, the thickness of the first depletion body 41 is greater than the thickness of the third depletion body 45, and the thickness of the third depletion body 45 is greater than the thickness of the second depletion body 43.

[0115] like Figure 1 , Figure 2, Figure 4 , Figure 5 , Figure 7 and Figure 8 As shown, in some embodiments, the first depletion body 41 and the second depletion body 43 are directly connected.

[0116] See also Figure 7 , Figure 7 A schematic structural diagram of an enhanced GaN power device provided in yet another embodiment of the present application.

[0117] like Figure 7 As shown, in some embodiments, the enhanced GaN power device further includes a second depletion layer 6 and a second gate 7, the second depletion layer 6 is disposed on the barrier layer 13 and between the source 2 and the first depletion layer 4, and the second gate 7 is disposed on the side of the second depletion layer 6 away from the barrier layer 13. By adding the second depletion layer 6 and the second gate 7, the first gate 5 and the second gate 7 can use the same control signal or asynchronous control signal to regulate the turn-on time between the first gate 5 and the second gate 7, thereby controlling the switching rate and switching loss of the device.

[0118] Optionally, the second depletion layer 6 is a P-type doped semiconductor.

[0119] Optionally, the semiconductor material of the second depletion layer 6 includes at least one of gallium nitride, aluminum gallium nitride, aluminum nitride or indium nitride.

[0120] like Figure 1 as well as Figures 4 to 7 As shown, in some embodiments, the first gate 5 is spaced apart from the source 2. That is, the enhancement mode GaN power device is a triode.

[0121] See also Figure 8 , Figure 8 A schematic structural diagram of an enhanced GaN power device provided in yet another embodiment of the present application.

[0122] like Figure 8 As shown, in some embodiments, the source 2 and the first gate 5 are short-circuited and serve as a cathode, and the drain 3 serves as an anode, so that the enhanced GaN power device is a diode. By short-circuiting the source 2 and the first gate 5, the parasitic resistance between the source 2 and the first gate 5 can be eliminated, thereby optimizing the conduction characteristics of the device.

[0123] Optionally, the source 2 and the first gate 5 can be short-circuited in a directly connected manner, or can be short-circuited by setting a bridge structure connection. In some optional embodiments, the source 2 and the first gate 5 are short-circuited in a directly connected manner to eliminate the spacing between the source 2 and the first gate. On the one hand, the volume of the device can be reduced under the same gate-drain spacing, and on the other hand, the gate-drain spacing can be increased under the same source-drain spacing to increase the withstand voltage performance.

[0124] In some embodiments, the source electrode 2 and the first gate electrode 5 are an integral structure. The source electrode 2 and the first gate electrode 5 are an integral structure, which means that the whole formed by the source electrode 2 and the first gate electrode 5 has good structural integrity, and there is no splicing transition area between the source electrode 2 and the first gate electrode 5, so the source electrode 2 and the first gate electrode 5 can be formed by a one-time molding process, thereby reducing the preparation steps.

[0125] like Figure 1 , Figure 2 as well as Figures 4 to 8 As shown, in some embodiments, the base 1 further includes a buffer layer 15 disposed on the side of the channel layer 11 away from the barrier layer 13 , a transition layer 17 disposed on the side of the buffer layer 15 away from the channel layer 11 , and a substrate 19 disposed on the side of the transition layer 17 away from the buffer layer 15 .

[0126] Optionally, the buffer layer 15 is a high resistance layer, and the material of the buffer layer 15 may be doped with carbon or iron to reduce the off-state leakage of the device and increase the breakdown voltage of the device.

[0127] Optionally, the material of the buffer layer 15 includes at least one of aluminum nitride or gallium nitride. On the one hand, the hole injection effect can compensate for the traps in the buffer layer 15, and on the other hand, the injected holes can recombine with the two-dimensional electron gas under the barrier layer 13 to emit light, and can also accelerate the recovery of the traps in the buffer layer 15.

[0128] Optionally, the material of the transition layer 17 includes at least one of aluminum nitride and gallium nitride. The transition layer 17 is used to balance the lattice and stress mismatch in epitaxy.

[0129] Depending on the epitaxial process and design, in some other embodiments, the transition layer is not a necessary layer structure.

[0130] Optionally, the material of the substrate 19 includes at least one of silicon, sapphire, aluminum nitride or silicon carbide.

[0131] Optionally, one or at least two depletion monomers 431 may be provided. When one depletion monomer 431 is provided, it is applicable to small-sized devices; when multiple depletion monomers 431 are provided, it is applicable to large-sized devices, and the more depletion monomers 431 there are, the larger the size of the applicable device is.

[0132] like Figure 1 as well as Figures 4 to 8 As shown, in some embodiments, at least two depletion monomers 431 are provided, and the at least two depletion monomers 431 are arranged along the second direction Y at equal intervals.

[0133] In these embodiments, the enhancement-mode GaN transistor further includes basic design structures such as a passivation layer and a field plate.

[0134] The above is only a specific implementation of the present application. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working process of the system described above can refer to the corresponding connection structure in the aforementioned system embodiment, which will not be repeated here. It should be understood that the protection scope of the present application is not limited to this. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application.

Claims

1. An enhanced GaN power device, characterized in that: include: A substrate, including a channel layer and a barrier layer for forming an electron gas channel; A source electrode and a drain electrode are arranged at intervals along a first direction and are electrically connected via the electron gas channel; A first depletion layer, disposed on the barrier layer and between the source and the drain, the first depletion layer comprising a first depletion body and a second depletion body, the second depletion body comprising a depletion monomer, the depletion monomer comprising a first end connected to the first depletion body and a second end spaced apart from the drain, and the depletion monomer defines a non-depletable region and a depletable region of the electron gas channel arranged along a second direction, the second direction intersecting the first direction; A first gate is disposed on the first depletion body and is in ohmic contact with the first depletion body.

2. The enhanced GaN power device according to claim 1, characterized in that: An absolute value of a difference between a depletion voltage of the depletion monomer and a depletion voltage of the depletable region is not greater than a preset value.

3. The enhanced GaN power device according to claim 1, characterized in that: A depletion voltage of the first terminal is greater than a depletion voltage of the second terminal.

4. The enhanced GaN power device according to claim 3, characterized in that: The width of the first end is greater than the width of the second end.

5. The enhancement mode GaN power device according to claim 1, characterized in that: Along the direction from the first end to the second end, the depletion voltage of the depletion monomer shows a gradually decreasing trend.

6. The enhancement mode GaN power device according to claim 5, characterized in that: Along the direction from the first end to the second end, the width of the depletion monomer shows a gradually decreasing trend.

7. The enhancement mode GaN power device according to claim 1, characterized in that: A depletion voltage of the first terminal is smaller than a depletion voltage of the second terminal.

8. The enhanced-mode GaN power device according to claim 7, characterized in that: The width of the first end is smaller than the width of the second end.

9. The enhancement mode GaN power device according to claim 1, characterized in that: Along the direction from the first end to the second end, the depletion voltage of the depletion monomer presents a gradually increasing trend.

10. The enhanced GaN power device according to claim 9, characterized in that: Along the direction from the first end to the second end, the width of the depletion monomer shows a gradually increasing trend.

11. The enhancement mode GaN power device according to claim 1, characterized in that: A depletion voltage of the first terminal is the same as a depletion voltage of the second terminal.

12. The enhancement mode GaN power device according to claim 11, characterized in that: The width of the first end is equal to the width of the second end.

13. The enhancement mode GaN power device according to claim 1, characterized in that: Along the direction from the first end to the second end, the variation coefficient of the depletion voltage of the depletion cell is 0.

14. The enhanced GaN power device according to claim 13, characterized in that: Along the direction from the first end to the second end, the depletion monomers are arranged with equal width.

15. The enhancement mode GaN power device according to claim 1, characterized in that: At least two depletion monomers are provided, and at least two of the depletion monomers are arranged at equal intervals along the second direction.

16. The enhancement mode GaN power device according to claim 1, characterized in that: The first depletion layer further includes a third depletion body, wherein the third depletion body is disposed between the first depletion body and the second depletion body, and the first depletion body and the second depletion body are connected via the third depletion body.

17. The enhancement mode GaN power device according to claim 1, characterized in that: The enhanced GaN power device further includes a second depletion layer and a second gate. The second depletion layer is disposed on the barrier layer and between the source and the first depletion layer. The second gate is disposed on a side of the second depletion layer away from the barrier layer.

18. The enhancement mode GaN power device according to claim 1, characterized in that: The first gate and the source are spaced apart from each other; or the first gate and the source are short-circuited.

19. The enhancement mode GaN power device according to claim 1, characterized in that: The base body further includes a buffer layer disposed on a side of the channel layer away from the barrier layer, a transition layer disposed on a side of the buffer layer away from the channel layer, and a substrate disposed on a side of the transition layer away from the buffer layer.

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