HEMT (High Electron Mobility Transistor) device with high-stability dynamic characteristic and preparation method thereof
By introducing a blocking layer, including a combination of an electric field redistribution layer and an insulating region, the problem of material interface instability caused by the electric field distribution of the gate and drain is solved, and high stability of dynamic characteristics and voltage resistance are achieved.
Patent Information
- Application Number
- CN202410027464.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-08
- Publication Date
- 2025-07-11
AI Technical Summary
The electric field distribution between the gate and drain of HEMT devices is concentrated on the device surface, resulting in unstable material interface and unstable dynamic characteristics, which is difficult to effectively solve in the prior art.
A blocking layer is introduced in the HEMT device, including a combination of an electric field redistribution layer and an insulating region, blocking the two-dimensional carrier gas channel between the source and drain, the gate no longer faces the drain electrode directly, and shields the drain electric field through the source, forming a fold-line current path to prevent the current from passing directly through the high electric field region.
It improves the dynamic characteristics stability of the device, reduces the risk of current collapse, enhances the voltage resistance of the device, while maintaining high and stable dynamic characteristics.
Smart Images
Figure CN120302667A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of HEMT devices, and particularly relates to a HEMT device with high-stable dynamic characteristics and a preparation method thereof. Background Art
[0002] The HEMT device is characterized in that the source electrode, drain electrode and gate electrode are all formed on the same plane of the device to form a planar device. Because during the operation of the device, the drain electrode is always connected to a high potential, for a planar device, there is always a side of the gate electrode facing the drain electrode, and the electric field distribution between the side of the gate electrode facing the drain electrode and the drain electrode is concentrated on the planar surface of the device. Therefore, for the HEMT device with planar device characteristics, due to the fact that the surface layer of the device between the gate electrode and the drain electrode is under the influence of the electric field for a long time, various unstable changes will occur at the material interface, such as charge accumulation, and even material property changes or functional degradation will occur on the material layer constituting the gate layer structure on the side of the gate electrode facing the drain electrode, ultimately leading to unstable dynamic characteristics of the device or even a large leakage current, resulting in device functional degradation or failure.
[0003] To address such problems, generally, passivation protection is added to the electrode plane of the HEMT device to make the surface state of the semiconductor material on the plane reach a stable state and is not easily affected by the electric field, or a gate field plate or a source field plate is added above the gate electrode, aiming to improve the electric field on the side of the gate electrode close to the drain electrode from the state of surface concentration to a state of dispersing a part of the electric field into the bulk material. Recent reports have also disclosed a method of extending the p-type GaN material under the gate metal in the direction of the drain electrode, which is similar to introducing a superjunction in the planar direction of the device to further reduce the aggregation of the electric field on the material surface.
[0004] In the prior art, adding a gate field plate and a source field plate is the most commonly used method, and this method has been widely applied in commercial HEMT device products. However, the electric field optimization effects produced by different field plate designs are different. Therefore, in order to improve the device breakdown voltage and optimize the dynamic characteristics of the device under high voltage, generally, a scheme of stacking multiple field plates is adopted. The fabrication of each layer of the field plate requires the deposition of insulating materials, photolithography and the fabrication of metal electrodes. Therefore, the fabrication cost of the device will increase significantly with the increase in the number of field plate layers, and it cannot completely eliminate the influence on the dynamic characteristics of the device. The method of extending the p-type GaN material under the gate metal in the direction of the drain electrode will have a greater impact on the two-dimensional carrier gas in the channel of the HEMT device between the gate electrode and the drain electrode, will increase the on-resistance of the device and also increase the gate-drain capacitance. At the same time, since the thickness of the extended p-type GaN material is required to be less than the thickness of the p-type GaN material under the gate metal, it also poses a very high challenge to the processing difficulty and the control of processing uniformity, and it is not easy to truly achieve commercialization.
[0005] In addition, existing HEMT devices basically all use hetero-substrate growth. Therefore, before forming the device functional layer, a buffer layer is grown on the substrate to improve the material quality of the device. However, the material quality of the buffer layer is generally lower than that of the device functional layer. When the device operates under high voltage and large current for a long time, a large amount of charge will be trapped in the buffer layer, and the two-dimensional carrier gas channel above this buffer layer with a large amount of trapped charge will be affected by the charge, forming a so-called virtual gate that affects the dynamic characteristics of the device. Summary of the Invention
[0006] To solve the above problems existing in the prior art, the present invention provides a HEMT device with high-stability dynamic characteristics and a preparation method thereof. The technical problems to be solved by the present invention are realized through the following technical solutions:
[0007] The present invention provides a HEMT device with high-stability dynamic characteristics, including: a two-dimensional carrier gas channel structure, and a source electrode, a drain electrode, and a gate electrode provided on the two-dimensional carrier gas channel structure; wherein,
[0008] The source electrode and the drain electrode are arranged adjacent to each other at an interval;
[0009] A first blocking region surrounding the source electrode is provided on the two-dimensional carrier gas channel structure, and there is an interval between the first blocking region and the source electrode; the first blocking region includes the gate electrode and a blocking layer, the blocking layer includes an electric field redistribution layer, or a combination of an electric field redistribution layer and an insulating region, and no current path is formed in the covered area of the blocking layer when the device is turned on;
[0010] Wherein, at least a part of the blocking layer in the first blocking region is closer to the drain electrode than the gate electrode, and the source electrode is closer to the drain electrode than at least a part of the gate electrode.
[0011] The present invention also provides a preparation method of a HEMT device with high-stability dynamic characteristics, applicable to the HEMT device with high-stability dynamic characteristics described in the above embodiments, including:
[0012] Prepare and form a two-dimensional carrier gas channel structure;
[0013] Grow an electric field redistribution layer on the upper surface of the two-dimensional carrier gas channel structure;
[0014] Remove a part of the electric field redistribution layer to expose the two-dimensional carrier gas channel structure, and prepare an insulating region at the exposed two-dimensional carrier gas channel structure, and the insulating region and the electric field redistribution layer form a blocking layer;
[0015] A source electrode, a drain electrode and a gate electrode are fabricated on the two-dimensional carrier gas channel structure, wherein the gate electrode and the blocking layer form a first blocking region surrounding the source electrode; the drain electrode is located on one side of the first blocking region; at least a part of the blocking layer in the first blocking region is closer to the drain electrode than the gate electrode; the source electrode is closer to the drain electrode than at least a part of the gate electrode; no current path is formed in the coverage area of the blocking layer when the device is turned on.
[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0017] HEMT device with high-stability dynamic characteristics and its manufacturing method. The HEMT device includes a two-dimensional carrier gas channel structure, and a source electrode, a drain electrode, and a gate electrode disposed on the two-dimensional carrier gas channel structure. Among them, the source electrode and the drain electrode are adjacent and spaced apart. A first blocking region surrounding the source electrode is disposed on the two-dimensional carrier gas channel structure, and there is a gap between the first blocking region and the source electrode. The first blocking region includes a gate electrode and a blocking layer. In the first blocking region, at least a part of the blocking layer is closer to the drain electrode than the gate electrode, and the source electrode is closer to the drain electrode than at least a part of the gate electrode. Different from the distribution modes of the source electrode, the drain electrode, and the gate electrode in the existing HEMT devices, the gate electrode of the HEMT device of the present invention is no longer between the source electrode and the drain electrode, but the source electrode is between the gate electrode and the drain electrode. In order to prevent a conductive channel from being directly generated between the source electrode and the drain electrode through the two-dimensional carrier gas, a blocking layer (including an electric field redistribution layer, or a combination of an electric field redistribution layer and an insulating region) is introduced between the source electrode and the drain electrode to block the two-dimensional carrier gas channel directly conducting between the source electrode and the drain electrode. That is, the gate electrode does not face the drain electrode directly, but the source electrode faces the drain electrode directly, and the direct shielding effect of the electric field of the drain electrode brought by the source electrode protects the gate electrode from the influence of the drain electrode electric field to the greatest extent. Due to the electric field redistribution layer or the combination of the electric field redistribution layer and the insulating region above the two-dimensional carrier gas channel between the source electrode and the drain electrode, that is, the blocking layer blocks the two-dimensional carrier gas channel directly conducting between the source electrode and the drain electrode, therefore, no current will pass through the region covered by the blocking layer between the source electrode and the drain electrode. Even if charge trapping occurs due to the action of the electric field on the buffer layer material in this region, it will not directly affect the dynamic characteristics of the device because it is far from the actual current conduction path. When the device is turned on, no current path is formed in the region covered by the blocking layer. The current path is a broken line from the drain electrode to the source electrode passing through the gate electrode and bypassing the region covered by the blocking layer. That is, the current path outside the blocking region is not a straight line but a broken line. According to the principle that current always selects the shortest path or the path with the smallest resistance, it is obvious that the current is not evenly distributed throughout the current path. The region with dense current is more likely to have surface charge trapping, resulting in the degradation of the current dynamic characteristics on this path. However, at this time, the region with sparse current originally will undertake the current shunt, which is equivalent to the entire current path being composed of several resistors in parallel. Since the resistance value of the two-dimensional carrier gas channel is very small, it can be considered that the resistance value differences between the above-mentioned several parallel resistors are very small. When there are defects on the surface of the device material in some regions to trap charges and cause current collapse, the parallel resistors in other regions can share the current, which is equivalent to setting sufficient redundant space for the current path from the source electrode to the drain electrode passing through the gate electrode. That is, the increase in the resistance value of some resistors in the several parallel resistors has little impact on the overall resistance value of the parallel resistors, greatly reducing the dynamic instability caused by the current collapse effect due to the significant increase in the overall dynamic resistance value between the gate and the drain in the traditional HEMT structure due to the influence of the electric field stress, thereby obtaining high-stable device dynamic characteristics.In addition, since the current path is not straight, it is also beneficial to prevent carriers from being continuously accelerated to too high an energy in the entire current path and then leaving the carrier channel material layer to enter the material surface layer or the device buffer layer material layer, where they are captured by defects, further reducing the risk of current collapse. Additionally, by setting the source electrode between the gate electrode and the drain electrode and introducing a blocking layer between the source electrode and the drain electrode, such a structural arrangement can not only improve the stability of the dynamic characteristics of the device, but also evenly distribute the electric field originally concentrated on the material surface between the source and the drain over the blocking layer and the device bulk material, that is, it can simultaneously improve the breakdown voltage capability of the device, enabling the device to maintain high-stability dynamic characteristics while improving the voltage tolerance capability.
[0018] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other objects, features, and advantages of the present invention more obvious and understandable, the following specific preferred embodiments are given, and in conjunction with the accompanying drawings, the details are described as follows. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 is a schematic diagram of a HEMT device with high-stability dynamic characteristics provided by an embodiment of the present invention;
[0020] Figure 2 is Figure 1 a schematic diagram of section 1 of the HEMT device with high-stability dynamic characteristics in
[0021] Figure 3 is Figure 1 a schematic diagram of section 2 of the HEMT device with high-stability dynamic characteristics in
[0022] Figure 4 is Figure 1 a schematic diagram of section 3 of the HEMT device with high-stability dynamic characteristics in
[0023] Figure 5 is Figure 1 a schematic diagram of section 4 of the HEMT device with high-stability dynamic characteristics in
[0024] Figure 6 is Figure 1 a schematic diagram of section 5 of the HEMT device with high-stability dynamic characteristics in
[0025] Figure 7 is a schematic diagram of another HEMT device with high-stability dynamic characteristics provided by an embodiment of the present invention;
[0026] Figure 8 is Figure 7 a schematic diagram of section 1 of the HEMT device with high-stability dynamic characteristics in
[0027] Figure 9 is Figure 7 A schematic diagram of cross-section 2 of a HEMT device with high stable dynamic characteristics;
[0028] Figure 10 is Figure 7 A schematic diagram of cross-section 3 of a HEMT device with high stable dynamic characteristics;
[0029] Figure 11 is Figure 7 A schematic diagram of cross-section 4 of a HEMT device with high stable dynamic characteristics;
[0030] Figure 12 is Figure 7 A schematic diagram of cross-section 5 of a HEMT device with high stable dynamic characteristics;
[0031] Figure 13 A schematic diagram of another HEMT device with high stable dynamic characteristics provided by an embodiment of the present invention;
[0032] Figure 14 is Figure 13 A schematic diagram of cross-section 1 of a HEMT device with high stable dynamic characteristics;
[0033] Figure 15 is Figure 13 A schematic diagram of cross-section 2 of a HEMT device with high stable dynamic characteristics;
[0034] Figure 16 is Figure 13 A schematic diagram of cross-section 3 of a HEMT device with high stable dynamic characteristics;
[0035] Figure 17 is Figure 13 A schematic diagram of cross-section 4 of a HEMT device with high stable dynamic characteristics;
[0036] Figure 18 A schematic diagram of another HEMT device with high stable dynamic characteristics provided by an embodiment of the present invention;
[0037] Figure 19 is Figure 18 A schematic diagram of cross-section 1 of a HEMT device with high stable dynamic characteristics;
[0038] Figure 20 is Figure 18 A schematic diagram of cross-section 2 of a HEMT device with high stable dynamic characteristics;
[0039] Figure 21 is Figure 18Schematic diagram of cross-section 3 of a HEMT device with high stable dynamic characteristics;
[0040] Figure 22 Schematic diagram of another HEMT device with high stable dynamic characteristics provided by an embodiment of the present invention;
[0041] Figure 23 is Figure 22 Schematic diagram of cross-section 1 of a HEMT device with high stable dynamic characteristics;
[0042] Figure 24 is Figure 22 Schematic diagram of cross-section 2 of a HEMT device with high stable dynamic characteristics;
[0043] Figure 25 is Figure 22 Schematic diagram of cross-section 3 of a HEMT device with high stable dynamic characteristics;
[0044] Figure 26 Schematic diagram of another HEMT device with high stable dynamic characteristics provided by an embodiment of the present invention;
[0045] Figure 27 is Figure 26 Schematic diagram of cross-section 1 of a HEMT device with high stable dynamic characteristics;
[0046] Figure 28 is Figure 26 Schematic diagram of cross-section 2 of a HEMT device with high stable dynamic characteristics;
[0047] Figure 29 is Figure 26 Schematic diagram of cross-section 3 of a HEMT device with high stable dynamic characteristics;
[0048] Figure 30 Schematic diagram of another HEMT device with high stable dynamic characteristics provided by an embodiment of the present invention;
[0049] Figure 31 is Figure 30 Schematic diagram of cross-section 1 of a HEMT device with high stable dynamic characteristics;
[0050] Figure 32 is Figure 30 Schematic diagram of cross-section 2 of a HEMT device with high stable dynamic characteristics;
[0051] Figure 33 is Figure 30 Schematic diagram of cross-section 3 of a HEMT device with high stable dynamic characteristics;
[0052] Figure 34Schematic diagram of a second blocking region provided by an embodiment of the present invention;
[0053] Figure 35 Schematic diagram of another second blocking region provided by an embodiment of the present invention.
[0054] Figure 36 Topological structure diagram of multiple HEMT devices provided by an embodiment of the present invention;
[0055] Figure 37 Schematic diagram of section 1 of 36;
[0056] Figure 38 is Figure 36 Schematic diagram of section 2 of;
[0057] Icon: 1 - Two - dimensional carrier gas channel structure; 2 - First blocking region; 3 - Electric field redistribution layer; 4 - Insulation region; 5 - Gate metal field plate; 6 - Source metal field plate; 7 - Second blocking region; S - Source, D - Drain; G - Gate. Detailed implementation manners
[0058] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following combines the accompanying drawings and specific implementation manners to detail a HEMT device with high - stability dynamic characteristics and its manufacturing method proposed according to the present invention.
[0059] The foregoing and other technical contents, features, and effects of the present invention can be clearly presented in the following detailed description of the specific implementation manners in conjunction with the accompanying drawings. Through the description of the specific implementation manners, a more in - depth and specific understanding of the technical means and effects adopted by the present invention to achieve the intended purpose can be obtained. However, the attached drawings are only for reference and illustration purposes and are not used to limit the technical solutions of the present invention.
[0060] In the first aspect, an embodiment of the present invention provides a HEMT device with high - stability dynamic characteristics. Please refer to Figure 1 , Figure 1 Schematic diagram of a HEMT device with high - stability dynamic characteristics provided by an embodiment of the present invention; The HEMT device with high - stability dynamic characteristics in this embodiment includes: a two - dimensional carrier gas channel structure 1 and a source S, a drain D, and a gate G disposed on the two - dimensional carrier gas channel structure 1.
[0061] Among them, the source electrode S and the drain electrode D are arranged adjacent to each other with a gap therebetween; a first blocking region 2 surrounding the source electrode S is provided on the two-dimensional carrier gas channel structure 1, and there is a gap between the first blocking region 2 and the source electrode S; the first blocking region 2 includes a gate electrode G and a blocking layer, and the blocking layer includes an electric field redistribution layer 3, or a combination of the electric field redistribution layer 3 and an insulating region 4, that is, the blocking layer can be the electric field redistribution layer 3, or the blocking layer can also be jointly formed by the electric field redistribution layer 3 and the insulating region 4. When the device is turned on, no current path is formed in the covered area of the blocking layer; among them, at least a part of the blocking layer in the first blocking region 2 is closer to the drain electrode D than the gate electrode G, and the source electrode S is closer to the drain electrode D than at least a part of the gate electrode G.
[0062] Optionally, the two-dimensional carrier gas channel structure 1 includes a channel layer and a barrier layer arranged in a stacked manner, and a two-dimensional carrier gas is formed between the channel layer and the barrier layer. Among them, the two-dimensional carrier gas can be a two-dimensional electron gas 2DEG or a two-dimensional hole gas 2DHG. The two-dimensional carrier gas channel structure 1 is located on a substrate layer. In other embodiments, other functional layers such as a cap layer can also be provided on the two-dimensional carrier gas channel structure 1, and other functional layers can also be inserted between the two-dimensional carrier gas channel structure and the substrate, but it does not affect the two-dimensional carrier gas channel structure and the topological distribution of the source electrode, drain electrode, and gate electrode proposed in the embodiments of the present invention on the two-dimensional carrier gas channel. It can be understood that the blocking layer described in the embodiments, that is, including the electric field redistribution layer, or a combination of the electric field redistribution layer and the insulating region, the blocking layer can also be a structure prepared by other materials or other preparation process methods that can make the carrier gas channel generated by the two-dimensional carrier gas structure below its covered area disappear, and it also does not affect the two-dimensional carrier gas channel structure and the topological distribution of the source electrode, drain electrode, and gate electrode proposed in the embodiments of the present invention on the two-dimensional carrier gas channel.
[0063] Optionally, the material of the barrier layer is generally an AlGaN material, and it can also be other GaN-based materials. The material of the channel layer is generally a GaN material, and it can also be other GaN-based materials. The bandgap width of the barrier layer material is greater than that of the channel layer material. The GaN-based materials can include GaN, BN, Al x Ga y In 1-x-y N(0≤x≤1, 0≤y≤1, 0≤x + y≤1) alloy materials, InP, GaAs, Al x Ga y In1 - x - yP(0≤x≤1, 0≤y≤1, 0≤x + y≤1) alloy materials, and Al x Ga y In 1-x-y As(0≤x≤1, 0≤y≤1, 0≤x + y≤1) alloy materials.
[0064] Optionally, the electric field redistribution layer 3 can be in a suspended state without electrodes, or can be connected to the source electrode S through a metal wire, or can be connected to other set potentials such as the gate, or can be connected to other external potentials.
[0065] In an alternative embodiment, the gate G can be in direct contact with the two-dimensional carrier gas channel structure 10 to form a depletion-mode HEMT device. Please refer to Figures 7 - 12 , in this embodiment, the blocking layer is the electric field redistribution layer 3, that is, the electric field redistribution layer 3 and the gate G form a first blocking region 2 surrounding the source electrode S. Optionally, when the two-dimensional carrier gas is a two-dimensional electron gas, the material of the electric field redistribution layer 3 is generally a p-type gallium nitride material, and when the two-dimensional carrier gas is a two-dimensional hole gas, the material of the electric field redistribution layer 3 is generally an n-type gallium nitride material.
[0066] Since the electric field redistribution layer 3 is introduced above the two-dimensional carrier gas channel structure 10 between the source electrode S and the drain electrode D, the two-dimensional carrier gas below it is depleted through the material of this layer, blocking the two-dimensional carrier gas channel that directly conducts between the source electrode S and the drain electrode D. Therefore, no current will pass through the area covered by the electric field redistribution layer 3 between the source electrode S and the drain electrode D. Even if charge trapping occurs in the buffer layer material in this area under the action of the electric field, it will not directly affect the dynamic characteristics of the device because it is far from the actual current conduction path. At the same time, the electric field redistribution layer 3 can also adjust the semiconductor surface electric field distribution between the source electrode S and the drain electrode D, avoiding material defects or material degradation in the material layer in the electrode material structure on the side of the gate G facing the drain electrode D due to the influence of the electric field.
[0067] In an alternative embodiment, the gate G can be a pGaN gate, that is, a p-type GaN layer is provided between the gate G and the two-dimensional carrier gas channel structure 10. Please refer to Figures 1 - 6 , in this embodiment, the blocking layer includes the electric field redistribution layer 3 and the insulating region 4, that is, the electric field redistribution layer 3, the insulating region 4 and the gate G form a first blocking region 2 surrounding the source electrode S, wherein, the electric field redistribution region formed by the gate G and the electric field redistribution layer 3 is isolated by the insulating region 4. Optionally, the material of the insulating region 4 can be made of materials such as SiO2, SiN, Al2O3, AlN, etc.
[0068] In an alternative embodiment, the gate G can also be a recessed gate, that is, the gate G is located in a recess provided in the top layer of the two-dimensional carrier gas channel structure 10, and the space between the gate G and the side wall and bottom of the recess is filled with an insulating material. Please refer to Figures 13 - 17, in this embodiment, the blocking layer includes an electric field redistribution layer 3 and an insulating region 4, that is, the electric field redistribution layer 3, the insulating region 4 and the gate G form a first blocking region 2 surrounding the source S, wherein the insulating region 4 isolates the electric field redistribution region formed by the gate G and the electric field redistribution layer 3. Optionally, the insulating material filled between the gate G and the sidewall of the groove may be the same as the insulating material of the insulating region 4, for example, materials such as SiO2, SiN, Al2O3, and AlN may be used.
[0069] Optionally, the insulating region 4 may be an insulating region formed by ion implantation extending from the surface of the two-dimensional carrier gas channel structure 1 to below the two-dimensional carrier gas interface. The insulating region 4 may also be an insulating region formed by etching from the surface of the two-dimensional carrier gas channel structure 1 to below the two-dimensional carrier gas interface to form an etching groove and then filling the insulating material.
[0070] Since the blocking layer above the two-dimensional carrier gas channel structure 10 between the source S and the drain D, i.e., the electric field redistribution layer 3 or the combination of the electric field redistribution layer 3 and the insulating region 4, blocks the two-dimensional carrier gas channel directly connected between the source S and the drain D, no current will flow through the area between the source S and the drain D covered by the blocking layer. Even if the buffer layer material in this area is subjected to the electric field and generates charge capture, it will not directly affect the dynamic characteristics of the device because it is far away from the actual current flow path. When the device is turned on, the area outside the area covered by the blocking layer can be a current path. Due to the existence of the blocking layer, the current path is not a straight line but a broken line. According to the principle that the current always selects the shortest path or the path with the smallest resistance, it is obvious that the current is not completely evenly distributed in the entire current path. The current-dense area is more likely to capture surface charges, resulting in the degradation of the current dynamic characteristics on this path. However, at this time, the area with sparse current will take over the current diversion, which is equivalent to the entire current path being formed by a number of resistors in parallel. Since the resistance of the two-dimensional carrier gas channel is originally very small, it can be considered that the resistance difference between the above-mentioned parallel resistors is very small. When there are defects on the surface of the device material in some areas that capture charges and cause current collapse, the parallel resistors in other areas can share the current, which is equivalent to setting up sufficient redundant space for the current path between the source S and the drain D through the gate G, greatly reducing the dynamic instability caused by the current collapse effect between the gate and the drain in the traditional HEMT structure, and obtaining highly stable device dynamic characteristics. At the same time, the electric field redistribution layer 3 can also adjust the semiconductor surface electric field distribution between the source S and the drain D, avoiding the material layer in the electrode material structure of the source S facing the drain D side and the gate G facing the drain D side being affected by the electric field to produce material defects or material degradation. Moreover, since the current path is not a straight line, it is also helpful to prevent carriers from being accelerated to too high an energy throughout the entire current path and passing through the carrier channel into the material surface and being captured by defects, further reducing the risk of current collapse.
[0071] In an optional embodiment, a connected gate metal field plate 5 may be provided on the gate G of the adjacent HEMT device, see Figures 18 - 21 There is an air bridge or an insulating medium filled between the gate metal field plate 5 and the top layer of the two-dimensional carrier gas channel structure 10, and a passivation protection layer is arranged on the device.
[0072] In an optional embodiment, a connected source metal field plate 6 may be provided on the source S of the adjacent HEMT device, see Figures 22 - 25 There is an air bridge or an insulating medium filled between the source metal field plate 6 and the top layer of the two-dimensional carrier gas channel structure 10, and a passivation protection layer is arranged on the device.
[0073] It can be understood that in the HEMT device of the above embodiment, the source S is located between the gate G and the drain D, and a blocking layer, that is, the electric field redistribution layer 3 or the combination of the electric field redistribution layer 3 and the insulating region 4, is introduced between the source S and the drain D to prevent a conductive channel from being directly generated between the source S and the drain D through the two-dimensional carrier gas. That is, the gate G does not face the drain D directly, but the source S faces the drain D directly. That is, the shortest straight-line path between the gate G and the drain D closest to it passes through the source S and the blocking layer, and the direct shielding effect of the drain D electric field brought by the source S and the blocking layer can protect the gate G from the influence of the drain D electric field to the greatest extent.
[0074] In other embodiments, the source S may not be located between the gate G and the drain D. Taking the pGaN gate as the gate G as an example, please refer to Figures 26 - 29 , optionally, in this embodiment, the blocking layer includes the electric field redistribution layer 3 and the insulating region 4, that is, the electric field redistribution layer 3, the insulating region 4 and the gate G form a first blocking region 2 surrounding the source S, and the gate G is located in the first blocking region 2 on the upper and lower sides of the source S, and the electric field redistribution region formed by the gate G and the electric field redistribution layer 3 is isolated by the insulating region 4. Please refer to Figures 30 - 33 , optionally, in this embodiment, the blocking layer includes the electric field redistribution layer 3 and the insulating region 4, that is, the electric field redistribution layer 3, the insulating region 4 and the gate G form a first blocking region 2 surrounding the source S, the gate G is located on the side of the first blocking region 2 far from the drain D and does not face the source S, and the electric field redistribution region formed by the gate G and the electric field redistribution layer 3 is isolated by the insulating region 4. It can be understood that in the above embodiment, the shortest straight-line path between the gate G and the drain D closest to it passes through the blocking layer, and the direct shielding effect of the drain D electric field brought by the blocking layer can protect the gate G from the influence of the drain D electric field to the greatest extent.
[0075] It should be noted that in the HEMT device of this embodiment, the two-dimensional carrier gas below the region covered by the blocking layer between the source S and the drain D is depleted, and current will not be conducted through the two-dimensional carrier gas channel in this region between the source S and the drain D. The two-dimensional carrier gas in the region not covered by the blocking layer can all be used as the current path between the source S and the drain D when the device is turned on, but all the current paths from the source S to the drain D are ultimately controlled by the gate G, that is, the gate G can complete the function of controlling the opening or closing of the current path between the source S and the drain D by regulating the two-dimensional carrier gas below the gate region.
[0076] In this embodiment, the function of the blocking layer is to prevent a current path from being formed in its covered area when the device is turned on. By combining its topological positions with those of the source electrode S, drain electrode D, and gate electrode G, sufficient redundant space is provided for the current path between the source electrode S and the drain electrode D passing through the gate G electrode, reducing the dynamic instability caused by the current collapse effect between the gate and the drain in the traditional HEMT structure, and obtaining a highly stable dynamic characteristic of the device.
[0077] It can be understood that, in addition to the blocking layer described in this embodiment, that is, including the electric field redistribution layer 3 or the combination of the electric field redistribution layer 3 and the insulating region 4, the blocking layer can also be a structure obtained by other materials or other preparation process methods that can make the carrier gas channel generated by the two-dimensional carrier gas structure under its covered area disappear.
[0078] In an alternative embodiment, the HEMT device further includes a second blocking region 7. Please refer to Figure 34 , optionally, the second blocking region 7 is disposed on the two-dimensional carrier gas channel structure 1. The edge of the second blocking region 7 has a recessed portion that is recessed towards the inside of the second blocking region 7. At least a part of the first blocking region 2 is located within the recessed portion, such that the second blocking region 7 forms a semi-surrounding structure for the first blocking region 2. At least a part of the second blocking region 7 is located between the drain electrode D and the first blocking region 2; there is a gap between the second blocking region 7 and the first blocking region 7; there is a gap between the second blocking region 7 and the drain electrode D.
[0079] In this embodiment, the second blocking region 7 plays a direct shielding role for the electric field of the drain electrode D. By using the second blocking region 7, the electric field stress influence from the drain electrode D can be blocked for the first blocking region 2.
[0080] It should be noted that Figure 34 the shape of the second blocking region 7 is only schematically shown in the illustrated embodiment. It can be understood that the opening direction of the recessed portion is not limited to the direction away from the drain electrode D shown in the figure.
[0081] Please refer to Figure 35 , optionally, the second blocking region 7 is disposed on the two-dimensional carrier gas channel structure 1 and is located inside the first blocking region 2. The edge of the second blocking region 7 has a recessed portion that is recessed towards the inside of the second blocking region 7. At least a part of the source electrode S is located within the recessed portion, such that the second blocking region 7 forms a semi-surrounding structure for the source electrode S; there is a gap between the second blocking region 7 and the first blocking region 2; there is a gap between the second blocking region 7 and the source electrode S.
[0082] In this embodiment, the second blocking region 7 plays a direct shielding role for the electric field of the drain electrode D. By using the second blocking region 7, the electric field stress influence from the drain electrode D can be reduced.
[0083] It should be noted that Figure 35The illustrated embodiment only schematically shows the shape of the second blocking region 7 . It is understandable that the opening direction of the recessed portion is not limited to the direction away from the drain electrode D as shown in the figure.
[0084] Optionally, the second blocking region 7 includes at least one of the electric field redistribution layer 3 and the insulating region 4, that is, the second blocking region 7 may be the electric field redistribution layer 3, or the second blocking region 7 may also be the insulating region 4, or the second blocking region 7 may also be formed by the electric field redistribution layer 3 and the insulating region 4. When the device is turned on, no current path is formed in the coverage area of the second blocking region 7.
[0085] It should be noted that Figures 1 - 35 The illustrated embodiment only schematically shows the shapes of the first blocking area 2 and the second blocking area 7. The shapes of the first blocking area 2 and the second blocking area 7 may also be other shapes besides rectangular rings, such as circular rings, polygonal rings, etc. The embodiments illustrated in the drawings cannot be used as limitations to the present invention.
[0086] In an optional embodiment, for a structure including a plurality of HEMT devices with highly stable dynamic characteristics, a HEMT device with highly stable dynamic characteristics serves as a device unit of the structure, wherein the drain D includes a first portion located on one side of the first blocking region and a second portion extending from an end of the first portion in a direction away from the first portion; optionally, at least a portion of the first portion forms an ohmic contact with the two-dimensional carrier gas channel structure 1. A p-type gallium nitride material is provided between at least a portion of the second portion and the two-dimensional carrier gas channel structure 1. That is, the p-type gallium nitride material is retained on the two-dimensional carrier gas channel structure 1 in a portion of the region, and a portion of the metal layer of the drain D covers the p-type gallium nitride material and is connected to the metal of the drain D that forms an ohmic contact on the two-dimensional carrier gas channel 1. For example, see Figures 36 - 38 , wherein the device unit in the structure is a HEMT device having a first blocking region and having highly stable dynamic characteristics.
[0087] Preferably, the drain metal in the portion directly adjacent to the drain D and the source S forms an ohmic contact with the two-dimensional carrier gas channel 1, and the drain metal in the gap region directly adjacent to the encirclement constituting the current flow path is in direct contact with the p-type gallium nitride material. The p-type gallium nitride material covered by the drain metal can provide additional hole injection for the current flow path, can neutralize electrons captured by defects in the material layer, and further improve the stability of the dynamic characteristics of the device.
[0088] The HEMT device with high-stability dynamic characteristics in this embodiment has a different distribution pattern of the source electrode, drain electrode, and gate electrode from that of existing HEMT devices. The gate electrode is no longer located between the source electrode and the drain electrode, but the source electrode is located between the gate electrode and the drain electrode. To prevent a conductive channel from being directly formed between the source electrode and the drain electrode through two-dimensional carrier gas, a blocking layer (including an electric field redistribution layer, or a combination of an electric field redistribution layer and an insulating region) is introduced between the source electrode and the drain electrode to block the two-dimensional carrier gas channel that directly conducts between the source electrode and the drain electrode. That is, the gate electrode does not face the drain electrode directly, but the source electrode faces the drain electrode directly, and the direct shielding effect of the electric field of the source electrode on the drain electrode maximally protects the gate electrode from the influence of the drain electrode electric field. Since the electric field redistribution layer above the two-dimensional carrier gas channel between the source electrode and the drain electrode blocks the two-dimensional carrier gas channel that directly conducts between the source electrode and the drain electrode, no current will pass through the region from the side of the source electrode facing the drain electrode to the side of the drain electrode facing the source electrode. Even if charge trapping occurs in the buffer layer material in this region under the action of the electric field, it will not directly affect the dynamic characteristics of the device because it is far from the actual current conduction path. When the device is turned on, no current path is formed in the covered area of the blocking layer, which is equivalent to providing sufficient redundant space for the current path passing through the gate electrode between the source electrode and the drain electrode. Therefore, high-stability device dynamic characteristics can be obtained.
[0089] In a second aspect, an embodiment of the present invention provides a method for manufacturing a HEMT device with high-stability dynamic characteristics, which is applicable to the HEMT device with high-stability dynamic characteristics provided in the first aspect above. The manufacturing method includes:
[0090] Step 1: Prepare and form a two-dimensional carrier gas channel structure;
[0091] Optionally, the two-dimensional carrier gas channel structure includes a channel layer and a barrier layer stacked, and two-dimensional carrier gas is formed between the channel layer and the barrier layer. Among them, the two-dimensional carrier gas can be two-dimensional electron gas (2DEG) or two-dimensional hole gas (2DHG).
[0092] Step 2: Grow an electric field redistribution layer on the upper surface of the two-dimensional carrier gas channel structure;
[0093] Optionally, the electric field redistribution layer can be directly grown above the two-dimensional carrier gas channel structure, or a cap layer can be first prepared on the two-dimensional carrier gas channel structure, and then the electric field redistribution layer is grown on the cap layer.
[0094] Step 3: Remove a part of the electric field redistribution layer to expose the two-dimensional carrier gas channel structure, and prepare an insulating region at the exposed two-dimensional carrier gas channel structure. The insulating region and the electric field redistribution layer form a blocking layer;
[0095] Optionally, part of the electric field redistribution layer can be removed by photolithography and etching processes to expose the two-dimensional carrier gas channel structure. Then, at the exposed two-dimensional carrier gas channel structure, photolithography and etching processes are used to etch below the interface between the barrier layer and the channel layer to form an insulating region, and an insulating material such as SiO2, SiN, Al2O3, AlN, etc. is deposited in the insulating region to fill the insulating region. Among them, the deposited insulating material can be a single material or multiple materials deposited layer by layer in sequence.
[0096] It should be noted that when depositing the insulating material in the insulating region, a passivation protection layer covering the electric field redistribution layer and the device material layer not covered by the electric field redistribution layer is formed simultaneously.
[0097] Step 4: Fabricate a source electrode, a drain electrode, and a gate electrode on the two-dimensional carrier gas channel structure. Among them, the gate electrode and the blocking layer form a first blocking region surrounding the source electrode; the drain electrode is located on one side of the first blocking region; in the first blocking region, at least a part of the blocking layer is closer to the drain electrode than the gate electrode; the source electrode is closer to the drain electrode than at least a part of the gate electrode; when the device is turned on, no current path is formed in the covered area of the blocking layer.
[0098] Optionally, first, part of the insulating material in the region not covered by the electric field redistribution layer can be removed by photolithography and etching processes until the surface of the device semiconductor material is exposed, while retaining the insulating material filled in the insulating region. Then, a metal is deposited and annealed to fabricate the source electrode and drain electrode ohmic contact electrodes. Finally, the gate electrode is processed in the gate region by photolithography and etching processes.
[0099] During the fabrication of the gate electrode, when the gate electrode is a pGaN gate, part of the region in the material of the part of the electric field redistribution layer region removed in step 3 does not include the gate region, that is, the material of the electric field redistribution layer in the gate region is used as the pGaN material part of the pGaN gate electrode, and a gate electrode metal electrode is fabricated above the pGaN material of the above pGaN gate electrode by photolithography, etching, metal deposition, and stripping processes.
[0100] When the gate electrode is a recessed gate, part of the region in the material of the part of the electric field redistribution layer region removed in step 3 includes the gate region. At this time, the material in the gate region needs to be removed by photolithography and etching methods until the part close to the two-dimensional carrier gas interface between the barrier layer and the channel layer in the two-dimensional carrier gas channel structure, or deep into the channel layer below the two-dimensional carrier gas interface between the barrier layer and the channel layer. Then, an insulating medium is deposited on the exposed material surface, and then the gate electrode metal electrode is obtained by metal deposition and stripping methods.
[0101] It is understandable that, excluding the related preparation processes for preparing the blocking layer described in this embodiment, that is, the process methods of depositing a pGaN layer, or forming an insulating region by ion implantation or etching trenches and depositing an insulating material, any material structure and preparation process obtained by other preparation process methods that can cause the carrier gas channel generated by the two-dimensional carrier gas structure under its coverage area to disappear fall within the protection scope of the present invention.
[0102] For the specific content of the preparation method of the HEMT device with high stable dynamic characteristics and the corresponding beneficial effects, please refer to the relevant content of the HEMT device with high stable dynamic characteristics provided in the first aspect, which will not be elaborated here.
[0103] 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 variant are intended to cover non-exclusive inclusion, so that an article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed. Without more limitations, the element defined by the statement "including one..." does not exclude the existence of another identical element in the article or device including the said element. "Connection" or "connected" and other similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The orientation or positional relationship indicated by "upper", "lower", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.
[0104] The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, which should all be regarded as falling within the protection scope of the present invention.
Claims
1. A HEMT device with high - stability dynamic characteristics, characterized in that, Comprising: A two-dimensional carrier gas channel structure, a source electrode, a drain electrode, and a gate electrode disposed on the two-dimensional carrier gas channel structure; wherein, The source electrode and the drain electrode are arranged adjacent to each other with a gap therebetween; A first blocking region surrounding the source electrode is provided on the two-dimensional carrier gas channel structure, and there is a gap between the first blocking region and the source electrode; the first blocking region includes the gate electrode and a blocking layer, and the blocking layer includes an electric field redistribution layer, or a combination of an electric field redistribution layer and an insulating region, and no current path is formed in the covered area of the blocking layer when the device is turned on; Wherein, in the first blocking region, at least a part of the blocking layer is closer to the drain electrode than the gate electrode, and the source electrode is closer to the drain electrode than at least a part of the gate electrode.
2. The HEMT device with high-stability dynamic characteristics according to claim 1, characterized in that, A second blocking region is provided on the two-dimensional carrier gas channel structure, and the edge of the second blocking region has a recessed portion recessed towards the inside of the second blocking region, and at least a part of the first blocking region is located in the recessed portion, so that the second blocking region forms a semi-surrounding structure for the first blocking region, and at least a part of the second blocking region is located between the drain electrode and the first blocking region; There is a gap between the second blocking region and the first blocking region; there is a gap between the second blocking region and the drain electrode.
3. The HEMT device with high-stability dynamic characteristics according to claim 1, wherein A second blocking region located inside the first blocking region is provided on the two-dimensional carrier gas channel structure, and the edge of the second blocking region has a recessed portion recessed towards the inside of the second blocking region, and at least a part of the source electrode is located in the recessed portion, so that the second blocking region forms a semi-surrounding structure for the source electrode; There is a gap between the second blocking region and the first blocking region; there is a gap between the second blocking region and the source electrode.
4. The HEMT device with high-stability dynamic characteristics according to claim 2 or 3, characterized in that, The second blocking region includes at least one of an electric field redistribution layer and an insulating region, and no current path is formed in the covered area of the second blocking region when the device is turned on.
5. The HEMT device with high-stability dynamic characteristics according to claim 1, wherein, The shortest straight-line path between the gate electrode and the drain electrode closest to it passes through the blocking layer or passes through the source electrode and the blocking layer.
6. The HEMT device with high-stability dynamic characteristics according to claim 1, characterized in that, The drain electrode includes a first part on one side of the first blocking region and a second part extending from the end of the first part in a direction away from the first part; At least a part of the first part forms an ohmic contact with the two-dimensional carrier gas channel structure.
7. The HEMT device with high-stability dynamic characteristics according to claim 6, wherein A p-type gallium nitride material is provided between at least a part of the second part and the two-dimensional carrier gas channel structure.
8. The HEMT device with high-stability dynamic characteristics according to claim 1, characterized in that, The material of the electric field redistribution layer includes p-type gallium nitride material.
9. The HEMT device with high-stability dynamic characteristics according to claim 1, characterized in that, In the first blocking region, an insulating region is provided between the gate electrode and the electric field redistribution region formed by the electric field redistribution layer.
10. The HEMT device with high-stability dynamic characteristics according to claim 1 or 9, characterized in that, The insulating region is an insulating region formed by ion implantation extending from the surface of the two-dimensional carrier gas channel structure to below the two-dimensional carrier gas interface.
11. The HEMT device with high-stability dynamic characteristics according to claim 1 or 9, characterized in that, The insulating region is an insulating region formed by etching from the surface of the two-dimensional carrier gas channel structure to below the two-dimensional carrier gas interface to form an etching groove and then filling the insulating material.
12. The HEMT device with high-stability dynamic characteristics according to claim 1, characterized in that, The electric field redistribution layer is at a floating potential or connected to a set potential, and the set potential is the source electrode or the gate electrode.
13. A preparation method of a HEMT device with high-stability dynamic characteristics, characterized in that, Applicable to the HEMT device with high-stability dynamic characteristics according to any one of claims 1-12, comprising: Preparing and forming a two-dimensional carrier gas channel structure; Growing an electric field redistribution layer on the upper surface of the two-dimensional carrier gas channel structure; Removing a part of the electric field redistribution layer to expose the two-dimensional carrier gas channel structure, and preparing an insulating region at the exposed two-dimensional carrier gas channel structure, wherein the insulating region and the electric field redistribution layer form a blocking layer; Preparing a source electrode, a drain electrode and a gate electrode on the two-dimensional carrier gas channel structure, wherein the gate electrode and the blocking layer form a first blocking region surrounding the source electrode; the drain electrode is located on one side of the first blocking region; at least a part of the blocking layer in the first blocking region is closer to the drain electrode than the gate electrode; the source electrode is closer to the drain electrode than at least a part of the gate electrode; no current path is formed in the coverage area of the blocking layer when the device is turned on.