Enhanced gan power device

Abstract

The embodiment of the present application provides a kind of enhanced GaN power device, it includes: base, including the channel layer of forming electron gas channel and barrier layer;Source and drain, interval arrangement and electrically connected along the first direction by electron gas channel;First depletion layer, is located on the barrier layer and between source and drain, first depletion layer includes first depletion body and second depletion body, second depletion body includes depletion monomer, depletion monomer includes the first end connected with first depletion body and the second end spaced apart from drain, and depletion monomer defines the non-depletable area and depletable area arranged along the second direction by electron gas channel, the second direction intersects with the first direction;First gate, is located on first depletion body and with first depletion body ohmic contact.The embodiment of the present application can not only optimize the electric field distribution when device is in off-state drain high voltage stress to improve breakdown voltage, but also can effectively inhibit the trap effect in device to optimize the dynamic resistance degradation problem of device.

Description

Technical Field

[0007]

[0001] This application relates to the field of semiconductor technology, and particularly to an enhanced GaN power device. Background Art

[0002] GaN power devices have advantages such as low on-resistance, low parasitic capacitance, and high switching speed. After years of development, GaN power devices have been widely used in consumer electronics. However, the performance of current GaN power devices still remains far from the physical theoretical limit of the material. To further optimize the performance of GaN devices, by optimizing the device structure design, reducing the sheet resistance of the device or increasing the breakdown voltage of the device, one commonly used device structure is the superjunction structure.

[0003] Power devices with a superjunction structure in the related art all require a normally-on two-dimensional electron gas channel, which does not conform to the enhanced technology required by power devices and will affect the reliability of the device and the power system.

[0004] Therefore, there is an urgent need for a new power device. Summary of the Invention

[0005] In view of the problems existing in the background art, the embodiments of the present application provide an enhanced GaN power device, which can not only optimize the electric field distribution when the device is in the off-state 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] The embodiments of the present application provide an enhanced GaN power device, which includes: a substrate including a channel layer and a barrier layer for forming an electron gas channel; a source electrode and a drain electrode spaced along a first direction and electrically connected through the electron gas channel; a first depletion layer provided on the barrier layer and located between the source electrode and the drain electrode, the first depletion layer includes a first depletion body and a second depletion body, the second depletion body includes depletion monomers, the depletion monomers include a first end connected to the first depletion body and a second end spaced from the drain electrode, and the depletion monomers define a non-depletable region and a depletable region arranged along a second direction in the electron gas channel, the second direction intersects with the first direction; a first gate provided on the first depletion body and in ohmic contact with the first depletion body.

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

[0008] According to any of the foregoing 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 foregoing 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 foregoing 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 foregoing 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 less than the width of the second end.

[0014] According to any of the foregoing 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 increasing trend.

[0015] According to any of the foregoing 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 foregoing 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 foregoing embodiments of the present application, along the direction from the first end to the second end, the change coefficient of the depletion voltage of the depletion monomer is 0.

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

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

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

[0022] According to any of the foregoing embodiments of the present application, the enhancement-mode GaN power device further includes a second depletion layer and a second gate, the second depletion layer is arranged on the barrier layer and located between the source electrode and the first depletion layer, and the second gate is arranged on the side of the second depletion layer away from the barrier layer.

[0023] According to any of the foregoing embodiments of the present application, the first gate and the source electrode are arranged at intervals; or, the first gate and the source electrode are short-circuited.

[0024] According to any of the foregoing embodiments of the present application, the substrate further includes a buffer layer disposed on a side of the channel layer背离the barrier layer, a transition layer disposed on a side of the buffer layer背离the channel layer, and a substrate disposed on a side of the transition layer背离the buffer layer.

[0025] In an embodiment of the present application, when the enhancement-mode GaN power device is in the off state, at a low drain high voltage, the holes provided by the depletion monomer and the two-dimensional electron gas in the depletable region can be quickly depleted laterally, causing the depletion region to expand rapidly. As the drain high voltage stress further increases, an electric field similar to a rectangular distribution will be formed in the depletion region along the direction from the drain to the first gate. From the perspective of semiconductor physics, due to the formation of a similar rectangular electric field distribution, the integral value of the electric field in the depletion region is higher. Therefore, the breakdown voltage of the enhancement-mode GaN power device is higher. In addition, when the enhancement-mode GaN power device is turned on, since the depletion monomer is connected to the first depletion body, movable holes can be provided for the depletion monomer through the first gate and the first depletion body. The movable holes can effectively shield the surface layer traps of the barrier layer. At the same time, since the first gate is prepared by ohmic contact on the first depletion body, when a positive bias voltage is applied to the first gate, both the first depletion body and the second depletion body can achieve the hole injection effect. The injected holes can recombine with the two-dimensional electron gas below the barrier layer to emit light, or 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 under the drain high voltage stress in the off state be optimized 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings. The drawings are not drawn to actual scale.

[0027] Figure 1 It is a schematic structural diagram of an enhancement-mode GaN power device provided by an embodiment of the present application;

[0028] Figure 2 is Figure 1 a cross-sectional view of the enhancement-mode GaN power device shown along the A-A direction;

[0029] Figure 3 is Figure 2 a schematic structural diagram of the electron gas channel in the enhancement-mode GaN power device shown;

[0030] Figure 4 It is a schematic structural diagram of an enhancement-mode GaN power device provided by another embodiment of the present application;

[0031] Figure 5Schematic diagram of the structure of an enhanced GaN power device provided by another embodiment of the present application;

[0032] Figure 6 Schematic diagram of the structure of an enhanced GaN power device provided by another embodiment of the present application;

[0033] Figure 7 Schematic diagram of the structure of an enhanced GaN power device provided by another embodiment of the present application;

[0034] Figure 8 Schematic diagram of the structure of an enhanced GaN power device provided by another embodiment of the present application.

[0035] Label description:

[0036] 1. Substrate; 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 electrode;

[0038] 3. Drain electrode;

[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. First gate electrode;

[0041] 6. Second depletion layer;

[0042] 7. Second gate electrode;

[0043] X. First direction; Y. Second direction. Detailed implementation manners

[0044] The features and exemplary embodiments of various aspects of the present application will be described in detail below. To make the objectives, technical solutions and advantages of the present application clearer and more understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. 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 some of these specific details. The following description of the embodiments is only provided to provide a better understanding of the present application by showing examples of the present application.

[0045] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, the elements defined by the statement "comprising..." do not exclude the existence of additional identical elements in the process, method, article or device comprising the said elements. Additionally, in this article, "a plurality of" means more than two, and "above" and "below" include the number itself.

[0046] GaN power devices have advantages such as low on-resistance, low parasitic capacitance and high switching speed. After years of development, GaN power devices have been widely used in consumer electronics. However, the performance of current GaN power devices still remains far from the physical theoretical limit of its materials. In order to further optimize the performance of GaN devices, by optimizing the device structure design, reducing the sheet resistance of the device or increasing the breakdown voltage of the device, one commonly used device structure is the superjunction structure. The power devices with superjunction structures in related technologies all require normally-on two-dimensional electron gas channels, which does not conform to the enhancement technology required by power devices 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 superjunction power device prepared by using the spontaneous polarization effect. It forms a superjunction by using electrons and holes formed by the spontaneous polarization effect. When the device is turned off, the paired electrons and holes can be quickly vertically depleted, causing the depletion region to quickly expand, thereby increasing the breakdown voltage of the device;

[0048] Related technology 2 (S. Han, J. Song, S. H. Yoo, 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 2.8kV Switching," IEEE Electron Device Lett., vol. 41, no. 12, pp. 1758-1761, Dec. 2020, DOI: 10.1109 / LED.2020.3029619.) discloses a superjunction structure that forms a superjunction through acceptor doping in p-GaN and donor doping on the barrier layer.

[0049] In addition, in the current manufacturing process of enhancement-mode GaN power devices, there are surface layer traps in the barrier layer and buffer layer traps in the buffer layer. When the device undergoes drain high-voltage stress, the surface layer traps and buffer layer traps will capture electrons, forming deep-level negative charge centers; after the device is turned on, these deep-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 problem of dynamic resistance degradation.

[0050] To solve the above technical problems, the embodiments of the present application provide an enhancement-mode GaN power device. By setting depletion monomers, the enhancement-mode GaN power device can optimize the electric field distribution when in the off-state drain high-voltage stress to further increase the breakdown voltage and suppress the dynamic resistance degradation problem of the enhancement-mode GaN power device.

[0051] Optionally, the shape of the enhancement-mode GaN power device can be square, rectangular, circular, irregular shape, etc., and the present application does not limit this.

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

[0053] To better understand the present application, the following Figures 1 to 8 will describe the enhancement-mode GaN power device in the embodiments of the present application in detail.

[0054] Please refer to Figures 1 to 3 , Figure 1 which is a schematic structural diagram of an enhancement-mode GaN power device provided by an embodiment of the present application; Figure 2 For Figure 1Cross-sectional view of the shown enhanced GaN power device along the A-A direction; Figure 3 is Figure 2 Schematic diagram of the structure of the electron gas channel in the shown enhanced GaN power device.

[0055] As Figures 1 to 3 shown, the enhanced GaN power device includes a substrate 1, a source electrode 2, a drain electrode 3, a first depletion layer 4, and a first gate electrode 5. The substrate 1 includes a channel layer 11 and a barrier layer 13 that form an electron gas channel 1A. The source electrode 2 and the drain electrode 3 are arranged at intervals along the first direction X and are electrically connected through the electron gas channel 1A. The first depletion layer 4 is disposed on the barrier layer 13 and is located between the source electrode 2 and the drain electrode 3. The first depletion layer 4 includes a first depletion body 41 and a second depletion body 43. The second depletion body 43 includes depletion monomers 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 electrode 3. And the depletion monomer 431 defines a non-depletable region 1B and a depletable region 1C arranged along the second direction Y in the electron gas channel 1A. The second direction Y intersects with the first direction X. The first gate electrode 5 is disposed 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 less than that 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 will form a two-dimensional electron gas with high concentration and high mobility in the electron gas channel 1A through spontaneous polarization and piezoelectric polarization effects.

[0059] As Figure 2 shown, optionally, when there is no bias voltage on the first gate electrode 5 or the gate-source voltage is 0V, there is no two-dimensional electron gas under the barrier layer 13 provided with the first depletion layer 4, forming an interruption 1D, that is, there is no two-dimensional electron gas in the region of the electron gas channel 1A corresponding to the first depletion layer 4, while there is initially a two-dimensional electron gas under the barrier layer 13 not provided with 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 for the interruption 1D, making the enhanced GaN power device an enhancement-mode device; when a positive bias voltage is applied to the first gate electrode 5, two-dimensional electron gas will be excited under the barrier layer 13 provided with the first depletion layer 4, that is, the interruption 1D is replenished with two-dimensional electron gas to make the electron gas channel 1A conductive, and the enhanced GaN power device is turned on.

[0060] As Figure 2As shown, optionally, the positive projection of the interruption 1D and the first depletion layer 4 on the barrier layer 13 coincides or substantially coincides; 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 characteristics, 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 characteristics, 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] Grow a layer of P-type doped semiconductor on the barrier layer 13;

[0071] Etch to form the first depletion body 41 and the second depletion body 43 respectively.

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

[0073] Prepare the first depletion body 41 on the barrier layer 13;

[0074] Grow another layer of P-type doped semiconductor on the barrier layer 13, and form the second depletion body 43 by photolithography and selective etching.

[0075] As Figure 3As shown, optionally, the non-exhaustible region 1B is a region of the electron gas channel 1A where there is no two-dimensional electron gas below the barrier layer 13 provided with the depletion monomer 431, that is, the interruption 1D includes the non-exhaustible region 1B.

[0076] Optionally, the positive projections of the non-exhaustible region 1B and the depletion monomer 431 on the barrier layer 13 coincide or are substantially coincident.

[0077] As Figure 2 and Figure 3 As shown, optionally, the exhaustible region 1C is a region of the electron gas channel 1A where there is initially a two-dimensional electron gas below the barrier layer 13 without the depletion monomer 431 provided between the first depletion body 41 and the drain 3.

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

[0079] In an embodiment of the present application, when the enhancement-mode GaN power device is in the off-state drain high-voltage stress, at low drain high voltage, the holes provided by the depletion monomer 431 and the two-dimensional electron gas in the exhaustible region 1C can be quickly depleted laterally, so that the depletion region quickly expands. 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. Analyzed from the semiconductor physics level, due to the formation of a similar rectangular electric field distribution, the integral value of the electric field in the depletion region is higher. Therefore, the breakdown voltage of the enhancement-mode GaN power device is higher. In addition, when the enhancement-mode GaN power device is turned on, since the depletion monomer 431 is connected to the first depletion body 41, movable holes can be provided for the depletion monomer 431 through the first gate 5 and the first depletion body 41, 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 is prepared on the first depletion body 41 by ohmic contact, when a positive bias voltage is applied to the first gate 5, both the first depletion body 41 and the second depletion body 43 can achieve the hole injection effect, and the injected holes can recombine with the two-dimensional electron gas below the barrier layer 13 to emit light, or the surface layer traps can be restored. That is, by setting the depletion monomer 431, not only can the electric field distribution of the device in the off-state drain high-voltage stress be optimized 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 enhancement-mode GaN power device approaches the breakdown electric field limit of the material of the enhancement-mode GaN power device. Among them, 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] Exemplarily, the average breakdown electric field of the enhanced GaN power device can 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 thicknesses of the first depletion body 41 and the second depletion body 43 can be set in various ways. For example, 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. Here, the direction from the channel layer 11 to the barrier layer 13 is the thickness direction.

[0084] For example, Figures 1 to 3 As shown, optionally, there are various ways to set the first direction X and the second direction Y, and the first direction X and the second direction Y can intersect at any preset angle. In some optional embodiments, the included angle between the first direction X and the second direction Y is 90 degrees. An included angle of 90 degrees between the first direction X and the second direction Y is more conducive to increasing the breakdown voltage.

[0085] For example, Figure 1 and Figure 2 As shown, in some embodiments, the source electrode 2 or / and 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 electrode 2 or / and the drain electrode 3 can also be set to be partially inserted into the barrier layer 13. <G

[0087] For example, 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 can also be set to be partially inserted into the barrier layer 13.

[0089] Optionally, when the enhanced GaN power device is in the off state, the depletion monomer 431 and the depletable region 1C can be depleted simultaneously or non-simultaneously.

[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 depleted non-simultaneously, the depletion monomer 431 and the depletable region 1C can assist each other in depletion. The optimization of the electric field distribution can also be achieved, and the smaller the difference in depletion between the depletion monomer 431 and the depletable region 1C, the more conducive it is 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 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 requirement for the breakdown voltage of the device, and the embodiments of the present application do not make specific limitations thereto.

[0093] In some embodiments, the depletion voltage of the first end 433 is greater than the depletion voltage of the second end 435. Since in the off state of the enhancement-mode GaN power device, the depletion monomer 431 and the depletable region 1C are depleted laterally, and the depletion voltage of the first end 433 is greater than the depletion voltage of the second end 435, therefore, near the position of the first gate 5, the two-dimensional electron gas in the depletable region 1C will be quickly depleted, and near the position of the drain 3, the depletion monomer 431 will be quickly depleted, thereby achieving a smaller parasitic capacitance and having 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] As Figure 1 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 and easier to implement, but also more precise in control.

[0096] As Figure 1 shown, in some embodiments, along the direction from the first end 433 to the second end 435, the depletion voltage of the depletion monomer 431 shows a gradually decreasing trend. This can avoid a sharp decrease in the depletion voltage of the depletion monomer 431 at a certain position along the direction from the first end 433 to the second end 435, which may affect the electric field distribution.

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

[0098] Optionally, the gradually decreasing trend can be a linear trend. That is, the depletion monomer 431 is trapezoidal.

[0099] Please refer to Figure 4 , Figure 4 which is a schematic structural diagram of an enhanced GaN power device provided by another embodiment of the present application.

[0100] As Figure 4 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 from the drain 3, it will cause the two-dimensional electron gas in the depletable region 1C to be less at the position close to the first gate 5 than at the position close to the drain 3. Therefore, the depletion voltage of the first end 433 being less than the depletion voltage of the second end 435 can make it easier to achieve charge balance or easier to ensure that the depletion monomer 431 and the two-dimensional electron gas are depleted simultaneously at the position close to the first gate 5 and the position close to the drain 3, so as to achieve 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 less than the width of the second end 435.

[0102] In some embodiments, along the direction from the first end 433 to the second end 435, the depletion voltage of the depletion monomer 431 shows a gradually increasing trend. This can avoid a sharp increase in the depletion voltage of the depletion monomer 431 at a certain position along the direction from the first end 433 to the second end 435, which may affect the electric field distribution.

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

[0104] Optionally, the gradually increasing trend can be a linear trend. That is, the depletion monomer 431 is trapezoidal.

[0105] Please refer toFigure 5 , Figure 5 Schematic diagram of a structure of an enhanced GaN power device provided in another embodiment of the present application.

[0106] As Figure 5 shown, in some embodiments, the depletion voltage of the first end 433 is the same as that of the second end 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, along the direction from the first end 433 to the second end 435, the variation coefficient of the depletion voltage of the depletion monomer 431 is 0. [[ID=Q16]]

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

[0110] Please refer to Figure 6 , Figure 6 [[ID=Q24]]Schematic diagram of a structure of an enhanced GaN power device provided in another embodiment of the present application.

[0111] As Figure 6 shown, in some embodiments, the first depletion layer 4 further includes a third depletion body 45. The third depletion body 45 is arranged 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 through the third depletion body 45. By providing the third depletion body 45, when the drain high-voltage stress is in the off state, the peak value of the electric field in the first gate 5 region can be reduced, 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 inventor 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, when the depletion region extends along the third depletion body 45 to the first gate 5, a high electric field will appear, deteriorating the breakdown 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 various setting methods for 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] As Figure 1 , Figure 2, Figure 4 , Figure 5 , Figure 7 and Figure 8 As shown in Figure 4 , Figure 5 , Figure 7 and Figure 8 , in some embodiments, the first depletion body 41 and the second depletion body 43 are directly connected.

[0116] Please refer to Figure 7 , Figure 7 which is a schematic structural diagram of an enhanced GaN power device provided by another embodiment of the present application.

[0117] As Figure 7 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 electrode 2 and the first depletion layer 4, and the second gate 7 is disposed on a 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 adopt the same control signal or asynchronous control signals 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, indium nitride, etc.

[0120] As Figure 1 and Figures 4 to 7 shown, in some embodiments, the first gate 5 and the source electrode 2 are spaced apart. That is, the enhanced GaN power device is a triode.

[0121] Please refer to Figure 8 , Figure 8 which is a schematic structural diagram of an enhanced GaN power device provided by another embodiment of the present application.

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

[0123] Optionally, the source electrode 2 and the first gate 5 can be shorted in a directly connected manner, or can be shorted by setting up a bridging structure. In some optional embodiments, the source electrode 2 and the first gate 5 are shorted in a directly connected manner to eliminate the spacing between the source electrode 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 breakdown voltage performance.

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

[0125] Such as Figure 1 、 Figure 2 and Figures 4 to 8 shown, in some embodiments, the substrate 1 further includes a buffer layer 15 provided on the side of the channel layer 11 away from the barrier layer 13, a transition layer 17 provided on the side of the buffer layer 15 away from the channel layer 11, and a substrate 19 provided 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 its material can be doped with carbon or iron to reduce the off-state leakage current of the device and improve 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, or can also accelerate the trap recovery of 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 the epitaxy.

[0129] According to different epitaxy processes and designs, 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, etc.

[0131] Optionally, one or at least two depletion monomers 431 can 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 the number of depletion monomers 431, the larger the size of the applicable devices.

[0132] Such asFigure 1 and Figures 4 to 8 As shown, in some embodiments, there are at least two depletion monomers 431, and the at least two depletion monomers 431 are arranged at equal intervals along the second direction Y.

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

[0134] As described above, only the specific embodiments of the present application are provided. Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working process of the above-described system can refer to the corresponding connection structures in the foregoing system embodiments, which will not be elaborated herein. It should be understood that the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should be covered within the protection scope of the present application.

Claims

1. An enhanced GaN power device, characterized in that, include: The substrate includes the channel layer and barrier layer that form the electron gas channel; The source and drain are spaced apart along a first direction and electrically connected via the electron gas channel; A first depletion layer is disposed on the barrier layer and located between the source and the drain. The first depletion layer includes a first depletion body and a second depletion body. The second depletion body includes a depletion monomer. The depletion monomer includes a first end connected to the first depletion body and a second end spaced apart from the drain. 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 intersects the first direction. A first gate is disposed on the first depletion body and is in ohmic contact with the first depletion body; Wherein, at least one of the first depletion body and the second depletion body is a P-type doped semiconductor, and the thickness of the first depletion body is greater than the thickness of the second depletion body.

2. The enhanced GaN power device according to claim 1, characterized in that, The absolute value of the difference between the depletion voltage of the depleted cell and the 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, The depletion voltage at the first terminal is greater than the depletion voltage at 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 enhanced 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 depleted cell shows a gradually decreasing trend.

6. The enhanced 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 depleted monomer gradually decreases.

7. The enhanced GaN power device according to claim 1, characterized in that, The depletion voltage of the first terminal is less than the depletion voltage of the second terminal.

8. The enhanced 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 enhanced 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 depleted cell shows 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 depleted monomer gradually increases.

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

12. The enhanced 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 enhanced GaN power device according to claim 1, characterized in that, Along the direction from the first end to the second end, the coefficient of change of the depletion voltage of the depleted cell is 0.

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

15. The enhanced GaN power device according to claim 1, characterized in that, The depleted monomers are provided in at least two, and the at least two depleted monomers are arranged at equal intervals along the second direction.

16. The enhanced GaN power device according to claim 1, characterized in that, The first depletion layer further includes a third depletion body, which is disposed between the first depletion body and the second depletion body, and the first depletion body and the second depletion body are connected through the third depletion body.

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

18. The enhanced GaN power device according to claim 1, characterized in that, The first gate is spaced apart from the source; or, the first gate is shorted to the source.

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

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