CN119342873A - Enhancement-mode GaN power devices - Google Patents

Abstract

The embodiment of the application provides an enhanced GaN power device which comprises a substrate, a source electrode, a drain electrode, a first depletion layer, a first grid electrode and a second grid electrode, wherein the substrate comprises a channel layer and a barrier layer which form an electron gas channel, the source electrode and the drain electrode are arranged at intervals along a first direction and are electrically connected through the electron gas channel, the first depletion layer is arranged on the barrier layer and is positioned 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, the depletion monomer comprises a first end connected with the first depletion body and a second end arranged at intervals with the drain electrode, the depletion monomer defines a non-depletable area and a depletable area which are distributed along a second direction, the second direction intersects 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 application, the electric field distribution of the device under the high-voltage stress of the off-state drain electrode can be optimized to improve the breakdown voltage, and the trap effect in the device can be effectively restrained to optimize the dynamic resistance degradation problem of the device.

Description

Enhanced GaN power device

Technical Field

The application relates to the technical field of semiconductors, in particular to an enhanced GaN power device.

Background

GaN power devices have advantages of low on-resistance, low parasitic capacitance, high switching rate, and the like, and have been widely used in consumer electronics through years of development. However, the performance of the GaN power device is still far from the physical theoretical limit of the material, so that in order to further optimize the performance of the GaN device, the square resistance of the device is reduced or the breakdown voltage of the device is increased by optimizing the structural design of the device, and one of the commonly adopted device structures is a super junction structure.

The power devices of the super junction structure in the related art all need a normally open two-dimensional electron gas channel, which is not consistent with the enhancement type technology needed by the power devices and can influence the reliability of the devices and the power systems.

Therefore, a new power device is needed.

Disclosure of Invention

In view of the problems existing in the background technology, the embodiment of the application provides an enhanced GaN power device, which not only can optimize the electric field distribution of the device under the high-voltage stress of an off-state drain to improve the breakdown voltage, but also can effectively inhibit the trap effect in the device to optimize the dynamic resistance degradation problem of the device.

The embodiment of the application provides an enhanced GaN power device which comprises a substrate, a source electrode, a drain electrode, a first depletion layer, a first grid electrode and a second grid electrode, wherein the substrate comprises a channel layer and a barrier layer which form an electron gas channel, the source electrode and the drain electrode are arranged at intervals along a first direction and are electrically connected through the electron gas channel, the first depletion layer is arranged on the barrier layer and positioned 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, the depletion monomer comprises a first end connected with the first depletion body and a second end arranged at intervals with the drain electrode, the depletion monomer defines a non-depletable region and a depletable region which are arranged along a second direction, the second direction intersects 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 an embodiment of the present application, an absolute value of a difference between the depletion voltage of the depletion monomer and the depletion voltage of the depletable region is not greater than a preset value.

According to any of the preceding embodiments of the application, the depletion voltage at the first terminal is greater than the depletion voltage at the second terminal.

According to any of the preceding embodiments of the application, the width of the first end is greater than the width of the second end.

According to any of the foregoing embodiments of the present application, the depletion voltage of the depleted monomer in the direction from the first end to the second end is gradually decreased.

According to any of the foregoing embodiments of the present application, the width of the depleted monomer in the direction from the first end to the second end is gradually reduced.

According to any of the preceding embodiments of the application, the depletion voltage at the first terminal is less than the depletion voltage at the second terminal.

According to any of the preceding embodiments of the application, the width of the first end is smaller than the width of the second end.

According to any of the foregoing embodiments of the present application, the depletion voltage of the depleted monomer in the direction from the first end to the second end is gradually increased.

According to any of the foregoing embodiments of the present application, the width of the depleted monomer in the direction from the first end to the second end is gradually increased.

According to any of the preceding embodiments of the application, the depletion voltage at the first terminal is the same as the depletion voltage at the second terminal.

According to any of the preceding embodiments of the application, the width of the first end is equal to the width of the second end.

According to any of the foregoing embodiments of the present application, the variation coefficient of the depletion voltage of the depletion monomer in the direction from the first end to the second end is 0.

According to any of the foregoing embodiments of the present application, the depleted monomers are equally wide disposed in a direction from the first end to the second end.

According to any of the foregoing embodiments of the present application, the depleted monomers are provided in at least two, and the at least two depleted monomers are equally spaced apart along the second direction.

According to any of the foregoing embodiments of the present application, the first depletion layer further includes a third depletion body provided 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.

According to any of the foregoing embodiments of the present application, the enhancement mode GaN power device further includes a second depletion layer disposed on the barrier layer and between the source and the first depletion layer, and a second gate disposed on a side of the second depletion layer facing away from the barrier layer.

According to any of the foregoing embodiments of the present application, the first gate is spaced apart from the source, or the first gate is shorted to the source.

According to any of the foregoing embodiments of the present application, the base further includes a buffer layer disposed on a side of the channel layer facing away from the barrier layer, a transition layer disposed on a side of the buffer layer facing away from the channel layer, and a substrate disposed on a side of the transition layer facing away from the buffer layer.

In the embodiment of the application, when the enhanced GaN power device is in an off state, under the conditions of low drain and high voltage, the two-dimensional electron gas provided by the depletion monomer and the depletion region can be rapidly and transversely depleted, so that the depletion region can be rapidly expanded. As the high-voltage stress of the drain electrode further increases, an electric field similar to a rectangular distribution along the drain electrode to the first gate electrode is formed in the depletion region, and the breakdown voltage of the enhanced GaN power device is higher because the electric field similar to a rectangular distribution is formed in the depletion region. In addition, when the enhanced GaN power device is started, the depleted monomer is connected with the first depleted body, movable holes can be provided for the depleted monomer through the first grid electrode and the first depleted body, the movable holes can effectively shield surface layer traps of the barrier layer, meanwhile, the first grid electrode is used for preparing the first depleted body through ohmic contact, when the first grid electrode is externally applied with positive bias, hole injection effect can be achieved by the first depleted body and the second depleted body, and injected holes can be combined with two-dimensional electron gas below the barrier layer to emit light, and recovery of the surface layer traps can be accelerated. The electric field distribution of the device under the high-voltage stress of the off-state drain electrode can be optimized by arranging the depletion monomer so as to improve the breakdown voltage, and the trap effect in the device can be effectively restrained so as to optimize the dynamic resistance degradation problem of the device.

Drawings

In order to more clearly illustrate the technical solution of the embodiments of the present application, the drawings that are needed to be used in the embodiments of the present application will be briefly described, and other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art. The figures are not drawn to true scale.

Fig. 1 is a schematic structural diagram of an enhanced GaN power device according to an embodiment of the present application;

FIG. 2 is a cross-sectional view of the enhanced GaN power device of FIG. 1 taken along the A-A direction;

FIG. 3 is a schematic diagram of an electron gas channel in the enhanced GaN power device of FIG. 2;

fig. 4 is a schematic structural diagram of an enhanced GaN power device according to another embodiment of the present application;

fig. 5 is a schematic structural diagram of an enhanced GaN power device according to another embodiment of the present application;

fig. 6 is a schematic structural diagram of an enhanced GaN power device according to another embodiment of the present application;

fig. 7 is a schematic structural diagram of an enhanced GaN power device according to another embodiment of the present application;

fig. 8 is a schematic structural diagram of an enhanced GaN power device according to another embodiment of the application.

Description of the reference numerals:

1. A substrate, an electron gas channel, a 1A non-depletable region, a1C depletable region, a 1D interrupt, a 11 channel layer, a 13 barrier layer, a 15 buffer layer, a 17 transition layer, a 19 substrate;

2. A source electrode;

3. a drain electrode;

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;

5. a first gate;

6. A second depletion layer;

7. a second gate;

X, a first direction, Y, a second direction.

Detailed Description

Features and exemplary embodiments of various aspects of the present application will be described in detail below, and in order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be described in further detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely configured to illustrate the application and are not configured to limit the application. It will be apparent to one skilled in the art that the present application may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the application by showing examples of the application.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising" does not exclude the presence of additional identical elements in a process, method, article, or apparatus that comprises the element. In the present specification, "a plurality of" means two or more, and "above" and "below" are inclusive.

GaN power devices have advantages of low on-resistance, low parasitic capacitance, high switching rate, and the like, and have been widely used in consumer electronics through years of development. However, the performance of the GaN power device is still far from the physical theoretical limit of the material, so that in order to further optimize the performance of the GaN device, the square resistance of the device is reduced or the breakdown voltage of the device is increased by optimizing the structural design of the device, and one of the commonly adopted device structures is a super junction structure. The power devices of the super junction structure in the related art all need a normally open two-dimensional electron gas channel, which is not consistent with the enhancement type technology needed by the power devices and can influence the reliability of the devices and the power systems. For example, the number of the cells to be processed,

The related art 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 adopting a spontaneous polarization effect, which adopts electrons and holes formed by the spontaneous polarization effect to form a super junction, when the device is turned off, paired electron and hole pairs can be rapidly and vertically exhausted, so that a depletion region is rapidly expanded, and the breakdown voltage of the device is improved;

related art 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 by acceptor doping in p-GaN and donor doping on a barrier layer.

In addition, in the existing enhanced GaN power device preparation process, a surface layer trap and a buffer layer trap exist in the barrier layer, when the device is subjected to high-voltage stress of a drain electrode, electrons can be captured by the surface layer trap and the buffer layer trap to form deep-level negative centers, and after the device is started, two-dimensional electron gas can be partially or completely consumed by the deep-level negative centers, so that the concentration of the two-dimensional electron gas is reduced, and the dynamic on-resistance of the device, namely the dynamic resistance degradation problem, is increased.

In order to solve the technical problems, the embodiment of the application provides an enhanced GaN power device, which can optimize the electric field distribution of the enhanced GaN power device when the enhanced GaN power device is under high-voltage stress of an off-state drain by arranging a depletion monomer so as to further improve breakdown voltage and inhibit the dynamic resistance degradation problem of the enhanced GaN power device.

Alternatively, the shape of the enhanced GaN power device may be square, rectangular, circular, irregular, etc., which the present application is not limited to.

Alternatively, the enhancement mode GaN power device may be a diode or a triode.

For a better understanding of the present application, the following describes in detail the enhancement mode GaN power device according to the embodiment of the present application with reference to fig. 1 to 8.

Referring to fig. 1 to 3 in combination, fig. 1 is a schematic structural diagram of an enhanced GaN power device according to an embodiment of the application, fig. 2 is a cross-sectional view along A-A direction of the enhanced GaN power device shown in fig. 1, and fig. 3 is a schematic structural diagram of an electron gas channel in the enhanced GaN power device shown in fig. 2.

As shown in fig. 1 to 3, the enhanced GaN power device includes a body 1, a source 2, a drain 3, a first depletion layer 4, and a first gate 5. The body 1 includes a channel layer 11 and a barrier layer 13 forming an electron gas channel 1A, a source 2 and a drain 3 are disposed at intervals along a first direction X and electrically connected via the electron gas channel 1A, a first depletion layer 4 is disposed on the barrier layer 13 and 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 disposed at intervals from the drain 3, and the depletion monomer 431 defines a non-depletable region 1B and a depletable region 1C arranged along a second direction Y intersecting the first direction X, and the first gate 5 is disposed on the first depletion body 41 and in ohmic contact with the first depletion body 41.

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

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.

Alternatively, the forbidden bandwidth of the channel layer 11 is smaller than that of the barrier layer 13, so that the channel layer 11 provides the 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 by spontaneous polarization and piezoelectric polarization effects.

As shown in fig. 2, alternatively, when no bias voltage is applied to the first gate 5 or the gate-source voltage is 0V, no two-dimensional electron gas is generated under the barrier layer 13 provided with the first depletion layer 4 to form an interruption 1D, that is, no two-dimensional electron gas is generated in the region of the electron gas channel 1A corresponding to the first depletion layer 4, and two-dimensional electron gas is initially generated under the barrier layer 13 provided with no first depletion layer 4, that is, a portion of the electron gas channel 1A except for the interruption 1D, so that the enhanced GaN power device is an enhanced device, and when a positive bias voltage is applied to the first gate 5, two-dimensional electron gas is excited under the barrier layer 13 provided 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 enhanced GaN power device is turned on.

As shown in fig. 2, alternatively, the front projection of the interruption 1D and the first depletion layer 4 on the barrier layer 13 coincide or substantially coincide, and the forward bias applied by the first gate 5 is not less than the threshold voltage of the first gate 5, so that the enhanced GaN power device is turned on.

Alternatively, the first depletion body 41 has a low resistance characteristic such that the first depletion body 41 has holes formed by ionization.

Alternatively, the first depletion body 41 is a P-type doped semiconductor.

Optionally, the P-type doping in the first depletion body 41 is active, has good conductive properties, and has holes formed by dopant ionization.

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

Alternatively, the second depletion body 43 has a low resistance characteristic such that the second depletion body 43 has holes formed by ionization.

Optionally, the second depletion body 43 is a P-doped semiconductor.

Optionally, the P-type doping in the second depletion body 43 is active, has good conductive properties, and has holes formed by dopant ionization.

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

Alternatively, the first depletion layer 4 may be prepared in various ways. In some alternative embodiments, the first depletion layer 4 may be prepared by:

Growing a P-type doped semiconductor layer on the barrier layer 13;

the first and second depletion bodies 41 and 43 are formed by etching, respectively.

In other embodiments, the first depletion layer 4 may also be prepared by:

preparing a first depletion body 41 on the barrier layer 13;

A P-type doped semiconductor is regrown on the barrier layer 13 and a second depletion body 43 is formed by photolithography and selective etching.

As shown in fig. 3, alternatively, the non-depletable region 1B is a region of the electron gas channel 1A without two-dimensional electron gas under the barrier layer 13 provided with the depletion monomer 431, i.e., the interruption 1D includes the non-depletable region 1B.

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

As shown in fig. 2 and 3, alternatively, the depletable region 1C is a region where the electron gas channel 1A of the two-dimensional electron gas initially exists below the barrier layer 13 between the first depletion body 41 and the drain electrode 3 where the depletion monomer 431 is not provided.

As shown in fig. 2 and 3, alternatively, 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.

In the embodiment of the application, when the enhancement mode GaN power device is under high-voltage stress of the off-state drain, the hole provided by the depletion monomer 431 and the two-dimensional electron gas of the depletable region 1C can be rapidly and laterally depleted under the high voltage of the low drain, so that the depletion region is rapidly expanded. As the high-voltage stress of the drain electrode 3 further increases, an electric field distributed like a rectangle between the drain electrode 3 and the first gate electrode 5 is formed in the depletion region, and the integrated value of the electric field in the depletion region is higher due to the formation of the electric field distributed like a rectangle, as analyzed from the semiconductor physical layer, so that the breakdown voltage of the enhanced GaN power device is higher. In addition, when the enhancement GaN power device is turned on, the depletion monomer 431 is connected with the first depletion body 41, movable holes can be provided for the depletion monomer 431 through the first grid electrode 5 and the first depletion body 41, the movable holes can effectively shield surface layer traps of the barrier layer 13, meanwhile, the first grid electrode 5 is in ohmic contact with the first depletion body 41, when the first grid electrode 5 is externally biased, the first depletion body 41 and the second depletion body 43 can realize hole injection effect, and the injected holes can be combined with two-dimensional electron gas below the barrier layer 13 to emit light, and can also be recovered by adding surface layer traps. Namely, by arranging the depletion monomer 431, not only the electric field distribution of the device under the high-voltage stress of the off-state drain electrode can be optimized to improve the breakdown voltage, but also the trap effect in the device can be effectively restrained to optimize the dynamic resistance degradation problem of the device.

Optionally, the average breakdown electric field of the enhanced GaN power device approximates 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.

Optionally, the breakdown electric field limit of the material of the enhanced GaN power device is 3.3MV/cm.

Illustratively, the average breakdown electric field of the enhanced GaN power device may be 3.29MV/cm, 3.28MV/cm, 3.27MV/cm, 3.26MV/cm, 3.27MV/cm, or the like.

Alternatively, the thickness of the first depletion body 41 and the thickness of the second depletion body 43 may be provided in various ways. In some alternative embodiments, as shown in fig. 1 and 2, the thickness of first depletion body 41 is greater than the thickness of second depletion body 43. The direction from the channel layer 11 to the barrier layer 13 is the thickness direction.

As shown in fig. 1 to 3, alternatively, the first direction X and the second direction Y may be arranged in a plurality of ways, and the first direction X and the second direction Y may intersect at any predetermined angle. In some alternative embodiments, the first direction X and the second direction Y are angled at 90 degrees. The angle between the first direction X and the second direction Y is 90 degrees, which is more beneficial to improving the breakdown voltage.

As shown in fig. 1 and 2, in some embodiments, the source 2 and/or drain 3 are provided on a surface of the barrier layer 13 on a side facing away from the channel layer 11.

In other embodiments, the source 2 and/or drain 3 may also be arranged to be partially inserted into the barrier layer 13.

As shown in fig. 1 and 2, in some embodiments, the first depletion layer 4 is provided on a surface of the barrier layer 13 on a side facing away from the channel layer 11.

In other embodiments, the first depletion layer 4 may also be arranged to be partially inserted into the barrier layer 13.

Alternatively, the depletion monomer 431 and the depletable region 1C may or may not be depleted simultaneously in the off-state of the enhanced GaN power device.

In alternative embodiments, the simultaneous depletion of the depletion monomer 431 and the depletion region 1C is more advantageous for optimizing the electric field distribution, thereby allowing higher breakdown voltages of the device.

In alternative embodiments, when the depletion monomer 431 and the depletion region 1C are not depleted at the same time, the depletion monomer 431 and the depletion region 1C may assist in depletion with each other. Optimization of electric field distribution can also be achieved, and the smaller the difference between depletion monomer 431 and depletion of depletion region 1C, the more favorable the optimization performance of electric field distribution.

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. Thereby controlling the difference between the depletion of the depletion monomer 431 and the depletion of the depletion region 1C within a certain range. The preset value may be set according to a requirement for a breakdown voltage of the device, which is not particularly limited in the embodiment of the present application.

In some embodiments, the depletion voltage at first end 433 is greater than the depletion voltage at second end 435. Since the depletion monomer 431 and the depletion region 1C are laterally depleted and the depletion voltage at the first end 433 is greater than the depletion voltage at the second end 435 when the enhancement mode GaN power device is in the off state, the two-dimensional electron gas of the depletion region 1C is rapidly depleted near the first gate 5, and the depletion monomer 431 is rapidly depleted near the drain 3, thereby realizing smaller parasitic capacitance and potentially functioning in higher frequency applications.

Alternatively, the depletion voltage of the depletion monomer 431 is equal to the depletion rate of the depletion monomer 431 and 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, and the depletion rate of the depletion monomer 431 can be controlled by adjusting the thickness and doping concentration of the depletion monomer 431.

In alternative embodiments, as shown in fig. 1, the width of the first end 433 is greater than the width of the second end 435. Controlling the depletion voltage at different locations of the depleted monomer 431 by adjusting the width of different locations of the depleted monomer 431 is not only simpler and easier to achieve, but also more accurate to control than controlling the depletion voltage at different locations of the depleted monomer 431 by adjusting the depletion rate at different locations of the depleted monomer 431.

As shown in fig. 1, in some embodiments, the depletion voltage of the depleted monomer 431 is in a decreasing trend along the direction from the first end 433 to the second end 435. It is possible to avoid influence of the electric field distribution by a sharp decrease in depletion voltage of the depletion monomer 431 at a position in the direction from the first end 433 to the second end 435.

As shown in fig. 1, in some embodiments, the width of the spent monomer 431 is in a gradual 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 the width of the depletable region 1C is correspondingly larger at a position closer to the drain 3. The variation trend of the depletion voltage of the depletion monomer 431 is controlled by adjusting the width variation of the depletion monomer 431, not only is easier to realize, but also is more accurate to control, compared to the variation trend of the depletion voltage of the depletion monomer 431 controlled by adjusting the variation of the depletion rate of the depletion monomer 431.

Alternatively, the gradual decrease trend may be a linear trend. I.e., the spent monomer 431 is trapezoidal in shape.

Referring to fig. 4, fig. 4 is a schematic structural diagram of an enhanced GaN power device according to another embodiment of the application.

As shown in fig. 4, in some embodiments, the depletion voltage at the first end 433 is less than the depletion voltage at the second end 435. Because the second end 435 is spaced from the drain electrode 3, the depletable region 1C has less two-dimensional electron gas near the first gate 5 than the depletable region 1C has near the drain electrode 3, and thus the depletion voltage of the first end 433 is smaller than that of the second end 435, so that charge balance is easier to achieve or simultaneous depletion of the depletion monomer 431 and the two-dimensional electron gas is easier to ensure at the position near the first gate 5 and the position near the drain electrode 3, thereby achieving more optimized electric field distribution to improve the breakdown voltage of the device.

In some embodiments, the width of the first end 433 is less than the width of the second end 435.

In some embodiments, the depletion voltage of the depleted monomer 431 is in a gradually increasing trend along the direction from the first end 433 to the second end 435. It is possible to avoid that the depletion voltage of the depletion monomer 431 increases sharply at a position in the direction from the first end 433 to the second end 435 to affect the electric field distribution.

In some embodiments, the width of the spent monomer 431 is in a gradual increasing trend along the direction from the first end 433 to the second end 435. That is, the width of the depletion monomer 431 is larger at a position closer to the drain 3, and the width of the depletable region 1C is smaller at a position closer to the drain 3.

Alternatively, the gradually increasing trend may be a linear trend. I.e., the spent monomer 431 is trapezoidal in shape.

Referring to fig. 5, fig. 5 is a schematic structural diagram of an enhanced GaN power device according to another embodiment of the application.

As shown in fig. 5, in some embodiments, the depletion voltage at the first terminal 433 is the same as the depletion voltage at the second terminal 435. The arrangement can meet the performance requirements of the device on parasitic capacitance and breakdown voltage.

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

In some embodiments, the coefficient of variation of the depletion voltage of the depletion monomer 431 in the direction from the first end 433 to the second end 435 is 0.

In some embodiments, the depleted monomer 431 is equally wide disposed in the direction from the first end 433 to the second end 435. I.e. the depleted monomer 431 is rectangular.

Referring to fig. 6, fig. 6 is a schematic structural diagram of an enhanced GaN power device according to another embodiment of the application.

As shown in fig. 6, in some embodiments, the first depletion layer 4 further includes a third depletion body 45, the third depletion body 45 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 off-state drain has high compressive stress, and the electric field concentration effect on one side of the first gate 5 is avoided, thereby improving the reliability and breakdown characteristics of the device. Further, the inventors 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, which may cause a high electric field to occur when the depletion region is extended to the first gate 5 along the third depletion body 45, the withstand voltage characteristics of the device are deteriorated.

Optionally, the third depletion body 45 is a P-doped semiconductor.

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

Alternatively, the thickness of the third depletion body 45 may be provided in a variety of ways. In alternative 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.

As shown in fig. 1,2, 4, 5, 7, and 8, in some embodiments, first depletion body 41 and second depletion body 43 are directly connected.

Referring to fig. 7, fig. 7 is a schematic structural diagram of an enhanced GaN power device according to another embodiment of the application.

As shown in fig. 7, in some embodiments, the enhancement mode GaN power device further includes a second depletion layer 6 and a second gate 7, the second depletion layer 6 being disposed on the barrier layer 13 and between the source 2 and the first depletion layer 4, the second gate 7 being disposed on a side of the second depletion layer 6 facing 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 signal to regulate and control the opening time between the first gate 5 and the second gate 7, so as to control the switching rate and the switching loss of the device.

Alternatively, the second depletion layer 6 is a P-type doped semiconductor.

Alternatively, the semiconductor material of the second depletion layer 6 includes at least one of gallium nitride, aluminum nitride, indium nitride, or the like.

As shown in fig. 1 and fig. 4 to 7, in some embodiments, the first gate 5 is spaced apart from the source 2. Namely, the enhanced GaN power device is a triode.

Referring to fig. 8, fig. 8 is a schematic structural diagram of an enhanced GaN power device according to another embodiment of the application.

As shown in fig. 8, in some embodiments, the source 2 is shorted to the first gate 5 and together acts as a cathode, and the drain 3 acts as an anode, such that the enhanced GaN power device is a diode. By shorting the source 2 to the first gate 5, parasitic resistance between the source 2 and the first gate 5 can be eliminated, thereby optimizing the on-characteristics of the device.

Alternatively, the source electrode 2 and the first gate electrode 5 may be shorted in a direct connection manner, or may be shorted by providing a bridge structure for connection. In alternative embodiments, the source 2 and the first gate 5 are shorted in a direct connection to eliminate the spacing between the source 2 and the first gate. On one hand, the volume of the device can be reduced under the condition of the same pitch of the same grid leakage, and on the other hand, the pitch of the grid leakage can be increased under the condition of the same pitch of the source leakage so as to increase the voltage resistance.

In some embodiments, the source 2 and the first gate 5 are of unitary construction. The integral structure of the source electrode 2 and the first gate electrode 5 means that the integral structure formed by the source electrode 2 and the first gate electrode 5 has good structural integrity, and no splicing transition area exists between the source electrode 2 and the first gate electrode 5, so that the source electrode 2 and the first gate electrode 5 can be formed through a one-step forming process, and the preparation steps can be reduced.

As shown in fig. 1,2 and 4 to 8, in some embodiments, the substrate 1 further includes a buffer layer 15 disposed on a side of the channel layer 11 facing away from the barrier layer 13, a transition layer 17 disposed on a side of the buffer layer 15 facing away from the channel layer 11, and a substrate 19 disposed on a side of the transition layer 17 facing away from the buffer layer 15.

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

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 the trap of the buffer layer 15, on the other hand, the injected holes can be combined with two-dimensional electron gas below the barrier layer 13 to emit light, and the trap recovery of the buffer layer 15 can be quickened.

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

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

Optionally, the material of the substrate 19 comprises at least one of silicon, sapphire, aluminum nitride, silicon carbide, or the like.

Alternatively, the depletion monomer 431 may be provided in one or at least two. When the depletion monomer 431 is provided in one, it is suitable for a small-sized device, and when the depletion monomer 431 is provided in a plurality, it is suitable for a large-sized device, and the larger the number of the depletion monomers 431 is, the larger the size of the suitable device is.

As shown in fig. 1 and fig. 4 to 8, in some embodiments, at least two depletion monomers 431 are provided, and at least two depletion monomers 431 are equally spaced apart along the second direction Y.

In these embodiments, the enhancement mode GaN transistor further includes a passivation layer and field plate, etc., base design structure.

In the foregoing, only the specific embodiments of the present application are described, and it will be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working process of the system described above may refer to the corresponding connection structure in the foregoing system embodiment, which is not repeated herein. It should be understood that the scope of the present application is not limited thereto, and any equivalent modifications or substitutions can be easily made by those skilled in the art within the technical scope of the present application, and they should be included in the scope of the present application.

Claims (19)

1. An enhanced GaN power device, comprising:

a substrate including a channel layer and a barrier layer forming an electron gas channel;

The source electrode and the drain electrode are arranged at intervals along the first direction and are electrically connected through the electron gas channel;

A first depletion layer disposed on the barrier layer and between the source and drain electrodes, the first depletion layer including a first depletion body and a second depletion body including a depletion monomer including a first end connected to the first depletion body and a second end spaced apart from the drain electrode, the depletion monomer defining the electron gas channel as a non-depletable region and a depletable region arranged along a second direction, the second direction intersecting the first direction;

and the first grid electrode is arranged on the first depletion body and in ohmic contact with the first depletion body.

2. The enhancement mode GaN power device of claim 1, wherein 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 enhancement mode GaN power device of claim 1, wherein the depletion voltage of the first terminal is greater than the depletion voltage of the second terminal.

4. The enhancement mode GaN power device of claim 3 wherein the width of said first end is greater than the width of said second end.

5. The enhancement mode GaN power device of claim 1, wherein the depletion voltage of the depleted monomer is in a decreasing trend along the direction from the first end to the second end.

6. The enhancement mode GaN power device of claim 5, wherein the width of said depleted monomer is in a gradual decreasing trend along the direction from said first end to said second end.

7. The enhancement mode GaN power device of claim 1, wherein the depletion voltage of the first terminal is less than the depletion voltage of the second terminal.

8. The enhancement mode GaN power device of claim 7, wherein a width of said first end is less than a width of said second end.

9. The enhancement mode GaN power device of claim 1, wherein the depletion voltage of the depleted monomer is in a gradual increasing trend along the direction from the first end to the second end.

10. The enhancement mode GaN power device of claim 9, wherein the width of said depleted monomer varies in a gradual increase in a direction from said first end to said second end.

11. The enhancement mode GaN power device of claim 1, wherein the depletion voltage at the first terminal is the same as the depletion voltage at the second terminal.

12. The enhancement mode GaN power device of claim 11, wherein a width of said first end is equal to a width of said second end.

13. The enhancement mode GaN power device of claim 1, wherein a coefficient of variation of a depletion voltage of said depletion monomer in a direction from said first end to said second end is 0.

14. The enhancement mode GaN power device of claim 13, wherein said depletion units are equally wide disposed along a direction from said first end to said second end.

15. The enhancement mode GaN power device of claim 1, wherein at least two of said depleted monomers are provided and wherein at least two of said depleted monomers are equally spaced apart along said second direction.

16. The enhancement-mode GaN power device of claim 1, wherein the first depletion layer further comprises a third depletion body 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 of claim 1 further comprising a second depletion layer disposed on the barrier layer between the source and the first depletion layer and a second gate disposed on a side of the second depletion layer facing away from the barrier layer.

18. The enhancement mode GaN power device of claim 1, wherein the first gate is spaced from the source or the first gate is shorted to the source.

19. The enhancement mode GaN power device of claim 1, wherein said body further comprises a buffer layer disposed on a side of said channel layer facing away from said barrier layer, a transition layer disposed on a side of said buffer layer facing away from said channel layer, and a substrate disposed on a side of said transition layer facing away from said buffer layer.