Fin-HEMT (High Electron Mobility Transistor) with aluminum oxide gallium nitride gallium oxide heterojunction and manufacturing method of Fin-HEMT

Abstract

The invention provides a Fin-HEMT (High Electron Mobility Transistor) with an aluminum oxide gallium nitride gallium oxide heterojunction and a manufacturing method of the Fin-HEMT. A buffer layer and a channel layer in the Fin-HEMT are sequentially arranged on a substrate; grooves are periodically etched in the channel layer along the gate width direction so as to construct and form a Fin structure; the doping layer and the barrier layer are sequentially arranged on the channel layer; wherein the channel layer is a beta-Ga2O3 layer, the doping layer is delta-Si doped beta-(AlxGa1-x) 2O3 as a delta modulation doping layer, an insertion channel layer is further arranged between the channel layer and the doping layer, the insertion channel layer is a GaN layer, the barrier layer is an unintentionally doped beta-(AlxGa1-x) 2O3 layer, and the barrier layer, the doping layer, the insertion channel layer and the channel layer are in contact to form a beta-(AlxGa1-x) 2O3 / GaN / Ga2O3 heterojunction structure. Two-dimensional electron gas is generated on one side, facing the doping layer, of the insertion channel layer; the grid electrode is arranged on the barrier layer. The Fin-HEMT is provided with a beta-(Al < x > Ga < 1-x >) < 2 > O < 3 > / GaN / Ga < 2 > O < 3 > heterojunction, 2DEG is generated on one side of an insertion channel layer at a heterojunction interface through deliberately doped delta-Si modulation, the channel mobility is improved, the on-resistance is reduced, and a certain improvement effect is achieved on the channel mobility by adopting a Fin structure.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to a Fin-HEMT having an aluminum gallium oxide-gallium nitride-gallium oxide heterojunction and a manufacturing method thereof. Background Art

[0002] Gallium oxide (Ga2O3) is an emerging ultra-wide bandgap semiconductor material. The most common crystal structures include α, β, γ, δ, ε and transitional κ phases, with band gaps of 4.8 to 5.2 eV and breakdown electric fields of up to 8 MV / cm. The most stable structure is the β phase, followed by the ε phase (with a transition temperature of 870°C), and the transition temperatures of the other three isomers are below 600°C. β-phase Ga2O3 is the most widely used due to its stability. Since the β phase is a non-polar phase, it cannot produce a high concentration of 2DEG at the heterojunction through spontaneous polarization, and needs to be produced through δ modulation doping. Although its mobility is not as good as that of GaAs and GaN, combined with the high critical breakdown electric field of the material, its saturation drift velocity has reached 1.8 to 2×10 7 cm / s, which is 1.2 times that of GaAs and 2.5 times that of GaN.

[0003] In the prior art, multi-threshold coupling can further improve device linearity. A common approach is to utilize a top gate and side gate in a fin structure to achieve multi-threshold coupling, but this conventional approach results in a loss of channel width between the fins. To combine the fin with a planar channel, improving linearity while avoiding loss of channel width, the present invention proposes a Fin-HEMT with an aluminum gallium oxide / gallium nitride / gallium oxide heterojunction and a method for fabricating the same. Summary of the Invention

[0004] Based on the above description, the present invention provides a Fin-HEMT having an aluminum gallium oxide-gallium nitride-gallium oxide heterojunction and a method for manufacturing the same, so as to provide a HEMT that improves linearity through multi-threshold coupling while improving device conduction capability by increasing the actual gate width.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] In a first aspect, the present invention provides a Fin-HEMT having an aluminum gallium oxide-gallium nitride-gallium oxide heterojunction, comprising: a substrate, a buffer layer, a channel layer, a doping layer, a barrier layer, and a gate;

[0007] The buffer layer and the channel layer are sequentially provided on the substrate;

[0008] The channel layer is periodically etched with grooves along the gate width direction to form a Fin structure;

[0009] The doping layer and the barrier layer are sequentially arranged on the channel layer to cover the entire wafer including the Fin structure; wherein the channel layer is a β-Ga2O3 layer, and the doping layer is a δ-Si doped β-(Al x Ga 1-x )2O3 as the δ modulation doping layer, an insertion channel layer is provided between the channel layer and the doping layer, the insertion channel layer is a GaN layer, and the barrier layer is an unintentionally doped β-(Al x Ga 1-x )2O3, the barrier layer, the doping layer, the insertion channel layer and the channel layer contact to form β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure, and generating a two-dimensional electron gas in the insertion channel layer on a side facing the doping layer;

[0010] The gate is disposed on the barrier layer.

[0011] On the basis of the above technical solution, the present invention can also be improved as follows.

[0012] Furthermore, the substrate is a high-resistance substrate.

[0013] Furthermore, the substrate is a SiC substrate, a GaN substrate or a Ga2O3 substrate.

[0014] Furthermore, the buffer layer is a Fe-doped β-Ga2O3 layer; and the channel layer is an unintentionally doped β-Ga2O3 layer.

[0015] Furthermore, the gate is a T-shaped gate;

[0016] The T-shaped gate structure is compatible with the Fin structure.

[0017] Furthermore, the Fin-HEMT having an aluminum gallium oxide, gallium nitride, and gallium oxide heterojunction further includes a source and a drain;

[0018] The source and the drain are both located on the upper side of the channel layer and are respectively located on the β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure on both sides along the gate length direction.

[0019] Furthermore, the Fin-HEMT having an aluminum gallium oxide-gallium nitride-gallium oxide heterojunction further includes a contact layer;

[0020] The contact layer is provided between the source electrode, the drain electrode and the channel layer.

[0021] In a second aspect, the present invention further provides a method for manufacturing a Fin-HEMT having an aluminum gallium oxide-gallium nitride-gallium oxide heterojunction as described in the first aspect, comprising:

[0022] sequentially growing a buffer layer and a channel layer on the substrate;

[0023] Performing mask deposition on the channel layer and selectively etching along the gate width direction to form a Fin structure;

[0024] The mask is removed, and the insertion channel layer, doping layer and barrier layer are deposited in sequence to form β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure;

[0025] In the β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure.

[0026] On the basis of the above technical solution, the present invention can also be improved as follows.

[0027] Furthermore, in the β-(Al x Ga 1-x Before making a gate on a 2O3 / GaN / Ga2O3 heterojunction structure, the following steps are also included:

[0028] Performing mask deposition and selective etching in the source and drain regions to obtain source and drain regions;

[0029] Depositing metal in the source region and the drain region, and then forming ohmic contacts by alloy annealing to obtain a source electrode and a drain electrode;

[0030] Alternatively, a heavily doped N-type β-Ga2O3 contact layer is grown in the source region and the drain region by regrowth, and the mask is removed; and metal is deposited on the heavily doped N-type β-Ga2O3 contact layer in the source region and the drain region to obtain a source electrode and a drain electrode respectively;

[0031] Wherein, the β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure.

[0032] Furthermore, the insertion channel layer, the doping layer and the barrier layer are deposited in sequence to form a β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure, specifically including:

[0033] Depositing unintentionally doped GaN as an inserted channel layer on the channel layer forming the Fin structure; depositing δ-Si doped β-(Al x Ga 1-x )2O3 as a δ modulation doping layer; then depositing unintentionally doped β-(Al x Ga 1-x )2O3 as a barrier layer, forming the β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure.

[0034] Compared with the prior art, the technical solution of this application has the following beneficial technical effects:

[0035] The Fin-HEMT with an aluminum gallium oxide, gallium nitride, and gallium oxide heterojunction provided by the present invention is provided with a substrate, a buffer layer, a channel layer, a doping layer, a barrier layer, and a gate; wherein the channel layer is periodically etched with grooves along the gate width direction to form a Fin structure; the doping layer and the barrier layer are sequentially provided on the channel layer to cover the entire wafer including the Fin structure; wherein the channel layer is a β-Ga2O3 layer, and the doping layer is a δ-Si doped β-(Al x Ga 1-x )2O3 is used as the δ modulation doping layer, and an inserted channel layer is provided between the channel layer and the doping layer. The inserted channel layer is a GaN layer. The advantages of the GaN inserted channel layer are: high material mobility; a large band gap with the barrier and back barrier, forming a quantum well to enhance the confinement of channel carriers; the barrier layer is an unintentionally doped β-(Al x Ga 1-x )2O3 layer, barrier layer, doping layer, inserted channel layer and channel layer contact to form β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure, and inserting the channel layer toward the side of the doped layer to generate two-dimensional electron gas. Not only does it not lose the channel width and two-dimensional electron gas concentration between the Fins, but it increases the channel width by about 2 times the Fin height relative to the planar device. Since the barrier layer on the sidewall is relatively thinner than the plane, the horizontal channel in the Fin structure is jointly controlled by the top gate and the side gate. The sidewall channel in the Fin structure is mainly controlled by the side gate, and the channel between the Fin-Fin is mainly controlled by the bottom gate, thereby further enhancing the multi-threshold coupling effect and improving the linearity of the device. β-(Al x Ga 1-x The 2O3 / GaN / Ga2O3 heterojunction structure uses intentionally doped δ-Si to generate a 2DEG on the GaN insertion channel layer side at the heterojunction interface, improving channel mobility and reducing on-resistance. The Fin structure also has a certain effect on improving channel mobility.

[0036] Compared with the prior art, the Fin-HEMT with an aluminum gallium oxide / gallium nitride / gallium oxide heterojunction and the method for manufacturing the same provided by the present invention have the following advantages:

[0037] (1) High conduction capability: Not only does the channel width and two-dimensional electron gas concentration between the fins not decrease, but the channel width is increased by about 2 times the fin height relative to the planar device.

[0038] (2) High linearity: The horizontal channel in the Fin structure realizes the joint control of the top gate and the side gate. The sidewall channel in the Fin structure is mainly controlled by the side gate, and the channel between Fin-Fin is mainly controlled by the bottom gate, thereby further enhancing the multi-threshold coupling effect and improving the linearity of the device.

[0039] (3) δ-Si modulated GaN channel: The δ-Si modulated doping layer generates a two-dimensional electron gas in the GaN insertion channel, which is not restricted by the polarization direction. The GaN insertion channel layer is connected to the front (Al x Ga 1-x )2O3 barrier layer and the Ga2O3 back barrier on the back have a large band step difference, thereby forming a GaN deep well channel and improving the two-dimensional electron gas concentration and confinement.

[0040] (4) High withstand voltage: β-Ga2O3 has a band gap of ~5eV and a critical breakdown field strength of ~8MV / cm, which effectively improves the withstand voltage characteristics of the device.

[0041] (5) High mobility: β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction channel can effectively improve the confinement and mobility of channel carriers. In addition, the channel mobility can be further improved through the Fin structure.

[0042] (6) High output power: High on-state current, combined with the high critical breakdown field strength of the material, enables the device to be used in high-voltage and high-current working scenarios to generate high output power.

[0043] (7) Low contact resistance: By regrowth of the source and drain regions, the channel 2DEG is ensured to be connected to the source and drain regions, which helps to form a good ohmic contact and simplifies the annealing process.

[0044] (8) Low side gate leakage: Compared with conventional Fin HEMT, the side gate is not in direct contact with the two-dimensional electron gas, but is in contact with the barrier layer similar to the top gate, which can effectively reduce the side gate leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1A schematic diagram of the three-dimensional structure of a Fin-HEMT having an aluminum gallium oxide, gallium nitride, and gallium oxide heterojunction provided in an embodiment of the present invention;

[0046] Figure 2 A schematic cross-sectional view of a Fin-HEMT having an aluminum gallium oxide, gallium nitride, and gallium oxide heterojunction provided in an embodiment of the present invention;

[0047] Figure 3 A schematic diagram of the fabrication process of a Fin-HEMT having an aluminum gallium oxide-gallium nitride-gallium oxide heterojunction provided in an embodiment of the present invention;

[0048] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0049] 1. Substrate;

[0050] 2. Buffer layer;

[0051] 3. Channel layer;

[0052] 4. Insert the channel layer;

[0053] 5. Doping layer;

[0054] 6. Barrier layer;

[0055] 7. Gate;

[0056] 8. Source;

[0057] 9. Drain;

[0058] 10. Contact layer. DETAILED DESCRIPTION

[0059] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings provide embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0060] Definitions of Abbreviations and Key Terms:

[0061] Ga2O3:Gallium Oxide

[0062] GaN: Gallium Nitrogen

[0063] GaAs: gallium arsenide

[0064] HEMT: High Electron Mobility Transistor

[0065] SiC: silicon carbide

[0066] 2DEG: two dimensional electron gas

[0067] AlN:aluminum nitirde, aluminum nitride

[0068] (Al x Ga 1-x )2O3:aluminum gallium nitride

[0069] In the existing technology, the existing Fin HEMT mainly includes the following two technologies: First, the GaN single-channel Fin HEMT based on the nitride barrier layer realizes the threshold coupling of the top gate and the side gate through the Fin structure to improve the linearity of the device. However, its defects are: the conventional AlGaN / GaN heterojunction has weak polarization strength and the 2DEG concentration is 1~2e 13 cm -2 The channel width between the fins is lost, which reduces the device's conduction characteristics; the barrier voltage resistance is poor. Secondly, the GaN single-channel FinHEMT based on the nitride barrier layer reduces the barrier layer in a certain area without completely etching it, thereby reducing but retaining the two-dimensional electron gas between the fins, and combining different barrier layer thicknesses to achieve threshold coupling and improve linearity. Its defects are: conventional AlGaN / GaN heterojunctions have weak polarization strength and low channel 2DEG concentration; thinning the barrier layer thickness between the fins causes 2DEG loss, reducing the device's conduction and breakdown characteristics; the fin depth is less than the barrier layer thickness, and there is no side gate coupling effect.

[0070] Based on this, the present invention provides a novel Fin-HEMT with an aluminum gallium oxide-gallium nitride-gallium oxide heterojunction. The embodiments of the present invention are further described in detail below with reference to the accompanying drawings and examples. The following examples are intended to illustrate the present invention but are not intended to limit the scope of the present invention.

[0071] First, as Figure 1 As shown, an embodiment of the present invention provides a Fin-HEMT with an aluminum gallium oxide-gallium nitride-gallium oxide heterojunction, comprising: a substrate 1, a buffer layer 2, a channel layer 3, a doping layer 5, a barrier layer 6 and a gate 7.

[0072] The buffer layer 2 and the channel layer 3 are sequentially provided on the substrate.

[0073] The channel layer 3 is periodically etched with grooves along the gate width direction to form a Fin structure.

[0074] The doping layer 5 and the barrier layer 6 are sequentially arranged on the channel layer 3; wherein the channel layer 3 is a β-Ga2O3 layer, and the doping layer 5 is a δ-Si doped β-(Al x Ga 1-x )2O3 as the δ modulation doping layer, there is an inserted channel layer 4 between the channel layer 3 and the doping layer 5, the inserted channel layer 4 is a GaN layer, and the barrier layer 6 is an unintentionally doped β-(Al x Ga 1-x )2O3 layer, barrier layer 6, doping layer 5, insertion channel layer 4 and channel layer 3 contact to form β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure, and a two-dimensional electron gas is generated on the side of the insertion channel layer 4 facing the doping layer.

[0075] The gate 7 is provided on the barrier layer 6. Preferably, the gate 7 is a T-shaped gate; the structure of the T-shaped gate is compatible with the structure of the Fin structure.

[0076] The core point of the embodiment of the present invention is to propose β-(Al x Ga 1-x β-Ga2O3 / GaN / Ga2O3 modulation-doped non-polar heterojunction channel: β-Ga2O3 modulation-doping generates a high concentration of 2DEG, avoiding polarization direction constraints. This allows for the simultaneous generation of 2DEG on one side of the inserted channel layer at both the horizontal and vertical sides of the heterojunction interface. Compared to conventional planar devices, this approach not only maintains the effective channel width but actually increases it by more than twice the Fin width. Compared to conventional Fin HEMTs, the side gates do not directly contact the 2D electron gas. Instead, they contact the barrier layer 6, similar to the top gate. This effectively reduces side gate leakage, and the wider bandgap of β-Ga2O3 gives the device a higher withstand voltage.

[0077] In addition, if Figure 1 As shown, the Fin channel and the planar channel are combined, and the horizontal channel in the Fin structure realizes the joint control of the top gate and the side gate. The sidewall channel in the Fin structure is mainly controlled by the side gate, and the channel between the Fin-Fin is mainly controlled by the bottom gate, thereby further enhancing the multi-threshold coupling effect and improving the linearity of the device without losing the channel width and two-dimensional electron gas concentration between the Fins.

[0078] Furthermore, the substrate 1 is a high-resistance substrate, preferably a SiC substrate, a GaN substrate or a Ga2O3 substrate.

[0079] The buffer layer 2 is a Fe-doped β-Ga2O3 layer; the channel layer 3 is an unintentionally doped β-Ga2O3 layer.

[0080] In an optional embodiment, the Fin-HEMT having the aluminum gallium oxide / gallium nitride / gallium oxide heterojunction further includes a source 8 and a drain 9 .

[0081] The source electrode 8 and the drain electrode 9 are both arranged on the same side of the channel layer 3 and are respectively arranged on the β-(Al x Ga 1-x ) on both sides of the 2O3 / GaN / Ga2O3 heterojunction structure.

[0082] Furthermore, in an optional embodiment, the Fin-HEMT having an aluminum gallium oxide / gallium nitride / gallium oxide heterojunction further includes a contact layer 10; a contact layer 10 is provided between the source electrode 8, the drain electrode 9, and the channel layer 3. The contact layer 10 is preferably a heavily doped N-type β-Ga2O3 contact layer.

[0083] The contact layer 10 can be grown first by regrowth, and then metal can be deposited on the contact layer 10 to obtain the source 8 and the drain 9; the metal can also be directly deposited on the channel layer 3, that is, after the regrowth and etching of the source and drain regions are completed, the secondary epitaxial regrowth can be omitted, and the ohmic metal can be directly deposited to make the 2DEG directly contact the sidewall metal, and then anneal to form a groove metal ohmic electrode.

[0084] The embodiment of the present invention is based on a non-polar β-Ga2O3 material system and proposes a Fin-HEMT with an aluminum oxide gallium nitride gallium oxide heterojunction. After selective etching is performed on a wafer epitaxial to a β-Ga2O3 channel layer, a δ-Si doped barrier layer, a GaN inserted channel layer and an unintentionally doped β phase (Al x Ga 1-x )2O3 barrier layer, forming β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction, so that the horizontal heterojunction in the Fin structure and the vertical heterojunction on the sidewall and the GaN inserted into the channel layer on the side of the horizontal heterojunction interface between Fin-Fin can produce 2DEG. Not only does it not lose the channel width and two-dimensional electron gas concentration between Fins, but it increases the channel width by about 2 times the Fin height relative to the planar device. Since the barrier layer on the sidewall is relatively thinner than the plane, the horizontal channel in the Fin structure is jointly controlled by the top gate and the side gate. The sidewall channel in the Fin structure is mainly controlled by the side gate, and the channel between Fin-Fin is mainly controlled by the bottom gate, thereby further enhancing the multi-threshold coupling effect and improving the linearity of the device. β-phase (Al x Ga 1-x)2O3 / GaN / Ga2O3 heterojunction structure, through intentional doping δ-Si modulation, generates 2DEG on the side of the GaN inserted channel layer at the heterojunction interface, thereby improving channel mobility and reducing on-resistance. By regrowth of the source and drain regions, it is ensured that each channel 2DEG is connected to the source and drain regions, which helps to form a good ohmic contact and simplifies the annealing process. The use of Fin structure has a certain effect on improving channel mobility. The prepared β-Ga2O3-based epitaxial channel and barrier T-Gate Fin-HEMT, that is, Fin-HEMT with aluminum oxide gallium nitride gallium oxide heterojunction, has the following technical effects:

[0085] (1) High conduction capability: Not only does the channel width and two-dimensional electron gas concentration between the fins not decrease, but the channel width is increased by about 2 times the fin height relative to the planar device.

[0086] (2) High linearity: The horizontal channel in the Fin structure realizes the joint control of the top gate and the side gate. The sidewall channel in the Fin structure is mainly controlled by the side gate, and the channel between Fin-Fin is mainly controlled by the bottom gate, thereby further enhancing the multi-threshold coupling effect and improving the linearity of the device.

[0087] (3) δ-Si modulated GaN channel: The δ-Si modulated doping layer generates a two-dimensional electron gas in the GaN insertion channel, which is not restricted by the polarization direction. The GaN insertion channel layer is connected to the front (Al x Ga 1-x )2O3 barrier layer and the Ga2O3 back barrier on the back have a large band step difference, thereby forming a GaN deep well channel and improving the two-dimensional electron gas concentration and confinement.

[0088] (4) High withstand voltage: β-Ga2O3 has a bandgap of ~5eV and a critical breakdown field strength of ~8MV / cm, which effectively improves the withstand voltage characteristics of the device;

[0089] (5) High mobility: β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction channel can effectively improve the confinement and mobility of channel carriers. In addition, the channel mobility can be further improved through the Fin structure.

[0090] (6) High output power: High on-state current, combined with the high critical breakdown field strength of the material, enables the device to be used in high-voltage and high-current working scenarios to generate high output power.

[0091] (7) Low contact resistance: By regrowth of the source and drain regions, the channel 2DEG is ensured to be connected to the source and drain regions, which helps to form a good ohmic contact and simplifies the annealing process.

[0092] (8) Low side gate leakage: Compared with conventional Fin HEMT, the side gate is not in direct contact with the two-dimensional electron gas, but is in contact with the barrier layer similar to the top gate, which can effectively reduce the side gate leakage.

[0093] In a second aspect, the present invention also provides a method for manufacturing a Fin-HEMT having an aluminum gallium oxide gallium nitride gallium oxide heterojunction, such as Figure 3 As shown, the operation is as follows:

[0094] Step S1: growing a buffer layer and a channel layer in sequence on a substrate.

[0095] Specifically, the substrates selected include but are not limited to various types of high-resistance substrates such as SiC, GaN, and Ga2O3. This embodiment takes a SiC substrate as an example, and grows a buffer layer and a channel layer on the substrate by MOCVD (metal organic chemical vapor deposition) or MBE (molecular beam epitaxy). The buffer layer can adopt an Fe-doped β-Ga2O3 structure with a thickness of T1, and the channel layer adopts an unintentionally doped β-Ga2O3 structure with a thickness of T2.

[0096] Step S2: performing mask deposition on the channel layer and selectively etching along the gate width direction to form a Fin structure.

[0097] Specifically, to prepare a Fin structure with side gate and top gate coupling control, a certain duty cycle is used for selective etching along the gate width direction in the active area, and the etching depth T3 (preferably 20 to 100 nm) is greater than the total thickness of the subsequent inserted channel layer, doping layer and barrier layer to ensure that the Fin structure has side gate control.

[0098] The mask can be a soft mask made of photoresist to simplify the process steps; a hard mask (including but not limited to various dielectric layers and metal masks such as SiO2, SiN, and Ni) can also be used to improve the etching profile and reduce process risks. Here, a SiO2 mask layer with a thickness of T4 is deposited as an example. After photolithographic stripping, the soft mask pattern is transferred to the hard mask. Subsequently, dry etching is performed using a Cl-based plasma, terminating in the channel layer structure to ensure that the deposited modulation layer and barrier layer remain epitaxially on the channel layer.

[0099] Step S3: remove the mask and deposit the insertion channel layer, doping layer and barrier layer in sequence to form β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure.

[0100] Specifically, after etching, the remaining mask layer is removed, and then a non-intentionally doped GaN layer with a thickness of T5 is deposited on the channel layer of the Fin structure using MBE as an inserted channel layer, and a δ-Si doped β-(Alx Ga 1-x )2O3 as a delta modulation doping layer, followed by the deposition of an unintentionally doped β-(Al x Ga 1-x )2O3 as a barrier layer, forming β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure. Due to the presence of the delta-modulated doping layer, 2DEG can be generated on the GaN insertion channel layer side within the fin structure and between the fin-fin structures. Furthermore, since it is not restricted by polarity, the heterojunction interface on the sidewalls of the fin structure can also generate 2DEG to form a channel, which is equivalent to increasing the gate width by twice the fin height (T3), improving the device's conduction capability.

[0101] Step S4: performing mask deposition and selective etching in the source and drain regions to obtain source and drain regions.

[0102] Specifically, to ensure good contact between the channel and the source and drain electrodes, the source and drain electrodes are produced by selective etching and regrowth. Since the secondary epitaxial β-Ga2O3 has a relatively large etching selectivity with the photoresist in Cl-based ICP etching, if high-power etching is performed for a long time, there will be a risk of glue sticking. The soft mask is difficult to meet the etching requirements, so a hard mask is used (including but not limited to various dielectric layers and metal masks: SiO2, SiN, Ni, etc.). Here, a SiO2 mask layer with a thickness of T8 deposited by sputtering is used as an example. After photolithographic stripping, the soft mask pattern is transferred to the hard mask, and then dry etching is performed using a Cl-based plasma. The etching is terminated in the channel layer structure, below the two-dimensional electron gas, to ensure that the highly doped regrowth can contact the 2DEG of the heterojunction channel.

[0103] There are two ways to deposit the source and drain electrodes:

[0104] Method 1: Use regrowth to grow heavily doped N-type β-Ga2O3 contact layers in the source region and drain region respectively, remove the mask; deposit metal on the heavily doped N-type β-Ga2O3 contact layers in the source region and drain region respectively to obtain the source and drain.

[0105] Specifically, MBE is used to re-grow the source and drain etched areas to grow a heavily doped N-type β-Ga2O3 contact layer, and then a BOE solution is used to remove the SiO2 mask.

[0106] After secondary epitaxy, source and drain metal electrodes are deposited using electron beam evaporation or magnetron sputtering. Ti / Al / Ni / Au are commonly used metal systems. If the regrowth doping concentration is not high enough to directly form a good ohmic contact, annealing can be performed to improve the contact. Annealing temperatures can range from 400°C to 900°C in a nitrogen atmosphere for 30 seconds to 1 minute. Active regions are then isolated using implantation or MESA etching.

[0107] Method 2: Deposit metal in the source and drain regions, and then form ohmic contacts by alloy annealing to obtain the source and drain.

[0108] Specifically, after the regrowth etching of the source and drain regions is completed, the secondary epitaxial regrowth can be omitted, and the ohmic metal can be directly deposited to make the 2DEG directly contact the sidewall metal, and then anneal to form a groove metal ohmic electrode.

[0109] Step S5: β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure.

[0110] Specifically, an electron beam lithography machine is used for gate electrode lithography, and PMMA series electronic photoresist is selected for three coats of photoresist. The sensitivity and resolution of the photoresist are changed by changing the baking temperature, and the appropriate exposure area and exposure dose are matched, so that the composite layer of photoresist forms a T-shaped gate electrode lithography morphology after one exposure and one development.

[0111] The gate metal is then deposited using electron beam evaporation or magnetron sputtering. The metal system can be selected from, but is not limited to, a Ni / Au combination. Because the sidewall barrier layer is relatively thinner than the planar layer, the horizontal channel in the Fin structure is controlled by both the top gate and the side gate. The sidewall channel in the Fin structure is primarily controlled by the side gate, while the channel between the Fins is primarily controlled by the bottom gate. This improves linearity through multi-threshold coupling while increasing the actual gate width to improve device conduction capability. After the gate electrode is deposited, it is peeled off, finally completing the key process steps of device fabrication.

[0112] Throughout this specification, reference to terms such as "specific examples" or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and integrate different embodiments or examples, and features of different embodiments or examples, described in this specification, unless otherwise mutually incompatible.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A Fin-HEMT having an aluminum gallium oxide / gallium nitride / gallium oxide heterojunction, characterized in that: include: Substrate, buffer layer, channel layer, doping layer, barrier layer and gate; The buffer layer and the channel layer are sequentially provided on the substrate; The channel layer is periodically etched with grooves along the gate width direction to form a Fin structure; The doping layer and the barrier layer are sequentially arranged on the channel layer to cover the entire wafer including the Fin structure; wherein the channel layer is a β-Ga2O3 layer, and the doping layer is a δ-Si doped β-(Al x Ga 1-x )2O3 as the δ modulation doping layer, an insertion channel layer is provided between the channel layer and the doping layer, the insertion channel layer is a GaN layer, and the barrier layer is an unintentionally doped β-(Al x Ga 1-x )2O3 layer, the barrier layer, the doping layer, the insertion channel layer and the channel layer contact to form β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure, and generating a two-dimensional electron gas on a side of the inserted channel layer facing the doping layer; The gate is disposed on the barrier layer.

2. The Fin-HEMT having an aluminum gallium oxide-gallium nitride-gallium oxide heterojunction according to claim 1, wherein: The substrate is a high-resistance substrate.

3. The Fin-HEMT having an aluminum gallium oxide-gallium nitride-gallium oxide heterojunction according to claim 2, wherein: The substrate is a SiC substrate, a GaN substrate or a Ga2O3 substrate.

4. The Fin-HEMT having an aluminum gallium oxide-gallium nitride-gallium oxide heterojunction according to claim 1, wherein: The buffer layer is a Fe-doped β-Ga2O3 layer; the channel layer is an unintentionally doped β-Ga2O3 layer.

5. The Fin-HEMT having an aluminum gallium oxide-gallium nitride-gallium oxide heterojunction according to claim 1, wherein: The gate is a T-shaped gate; The T-shaped gate structure is compatible with the Fin structure.

6. The Fin-HEMT having an aluminum gallium oxide-gallium nitride-gallium oxide heterojunction according to claim 1, wherein: The Fin-HEMT having an aluminum gallium oxide-gallium nitride-gallium oxide heterojunction further includes a source and a drain; The source and the drain are both located on the upper side of the channel layer and are respectively located on the β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure on both sides along the gate length direction.

7. The Fin-HEMT having an aluminum gallium oxide-gallium nitride-gallium oxide heterojunction according to claim 6, wherein: The Fin-HEMT having an aluminum gallium oxide-gallium nitride-gallium oxide heterojunction further includes a contact layer; The contact layer is provided between the source electrode, the drain electrode and the channel layer.

8. A method for manufacturing a Fin-HEMT having an aluminum gallium oxide-gallium nitride-gallium oxide heterojunction according to any one of claims 1 to 7, characterized in that: include: sequentially growing a buffer layer and a channel layer on the substrate; Performing mask deposition on the channel layer and selectively etching along the gate width direction to form a Fin structure; The mask is removed, and the insertion channel layer, doping layer and barrier layer are deposited in sequence to form β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure; In the β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure.

9. The production method according to claim 8, characterized in that: In the β-(Al x Ga 1-x Before making a gate on a 2O3 / GaN / Ga2O3 heterojunction structure, the following steps are also included: Performing mask deposition and selective etching in the source and drain regions to obtain source and drain regions; Depositing metal in the source region and the drain region, and then forming ohmic contacts by alloy annealing to obtain a source electrode and a drain electrode; Alternatively, a heavily doped N-type β-Ga2O3 contact layer is grown in the source region and the drain region by regrowth, and the mask is removed; and metal is deposited on the heavily doped N-type β-Ga2O3 contact layer in the source region and the drain region to obtain a source electrode and a drain electrode respectively; Wherein, the β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure.

10. The manufacturing method according to claim 8, characterized in that: The insertion channel layer, the doping layer and the barrier layer are deposited in sequence to form a β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure, specifically including: Depositing unintentionally doped GaN as an inserted channel layer on the channel layer forming the Fin structure; depositing δ-Si doped β-(Al x Ga 1-x )2O3 as a δ modulation doping layer; then depositing unintentionally doped β-(Al x Ga 1-x )2O3 as a barrier layer, forming the β-(Al x Ga 1-x )2O3 / GaN / Ga2O3 heterojunction structure.

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