Semiconductor device with hollow cavity

Abstract

The present invention relates to a semiconductor device (100), comprising: a semiconductor substrate (110); an aluminum gallium-nitride (AlGaN) back barrier layer (121) formed above the semiconductor substrate (110); a GaN channel layer (122) formed on the AlGaN back barrier layer (121), wherein a two-dimensional hole gas (2DHG) is formed on a contact surface (123) between the GaN channel layer (122) and the AlGaN back barrier layer (121); and a p-type doped region (101) formed above the semiconductor substrate (110) and adjacent to the GaN channel layer (122) and the AlGaN back barrier layer (121). The p-type doped region (101) provides ohmic contact for the two-dimensional hole gas formed on the contact surface (123) between the GaN channel layer (122) and the AlGaN back barrier layer (121). The p-type doped region (101) includes magnesium as a p-type dopant. The p-type doped region (101) includes one or more hollow cavities (102) extending from the top surface (101a) of the p-type doped region (101). The hollow cavities (102) form escape channels for hydrogen atoms, which are formed during dopant activation of the p-type doped region (101) during the fabrication of the semiconductor device (100).

Description

Technical Field

[0001] This invention relates to the fields of semiconductor devices and power device applications. Specifically, this invention relates to gallium nitride (GaN) technology for power device applications. Background Technology

[0002] A key step in using GaN technology for power, radio frequency (RF), and LED applications is the proper activation of dopant elements in the device, enabling the formation of heavily doped n-type and p-type regions, ultimately leading to a pn junction. Forming heavily doped p-type regions is particularly challenging in wide-bandgap technologies like GaN. The first reason is the significant distance between the acceptor energy level and the valence band edge. For example, magnesium, commonly used for p-type doping in GaN, has activation energies in the 170-200 meV range. The second reason is the complex formation of aggregates, which hinders efficient dopant activation. A primary mechanism is believed to be the formation of Mg-H complexes. These complexes prevent magnesium from entering the substitutional lattice junctions. Efficient dopant activation in deep trenches is crucial for all future vertical and semi-vertical power MOSFETs employing GaN technology. Beyond process flow details, a key factor for successful implementation is the complete activation of the p-type GaN layer within the deep trench, e.g., the proper activation of the dopant element (in this case, Mg). Summary of the Invention

[0003] This invention provides a technical solution for the efficient activation of dopants in deep trenches.

[0004] Specifically, the present invention provides a technical solution for a semiconductor device (especially using GaN technology), which uses highly doped n-type and p-type regions.

[0005] The above and other objectives are achieved through the features of the independent claim. Other implementations will be apparent from the dependent claims, the description, and the drawings.

[0006] This invention proposes a new technique for efficient dopant activation of p-type materials using GaN technology. GaN technology is particularly well-suited for use with deep trenches filled with doped material, where conventional activation techniques are insufficient to achieve satisfactory dopant activation. The advantages of this new technique, as described below, can be summarized as follows: it enables efficient dopant activation in deep trenches; it can be combined with p-type deep trenches connecting to a source of two-dimensional hole gas (2DHG); and it minimizes dynamic effects and current collapse, which are major challenges in the successful development of GaN technology for RF and power applications. This new technique is also suitable for realizing vertical GaN power transistors, as the operation of such devices requires buried deep p-type doped regions.

[0007] To describe the invention in detail, the following terms, abbreviations, and symbols are used:

[0008] GaN (Gallium Nitride)

[0009] RF (Radio Frequency)

[0010] MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor)

[0011] 2DHG (Two-dimensional hole gas)

[0012] 2DEG (Two-dimensional electron gas)

[0013] UID (Unintentionally Doped)

[0014] HEMT (High Electron Mobility Transistor)

[0015] RDSON on-resistance between drain and source terminals

[0016] This invention describes semiconductor devices employing GaN technology. GaN technology is currently being developed as an alternative to traditional silicon technology for power electronics applications. Polarization charge is one of the key components of GaN technology and can be used to achieve better performance than silicon technology. A normally off p-GaN HEMT can be represented by a silicon substrate as the base material and a nitride-based epitaxial layer grown on the silicon substrate. This complex epitaxial layer can consist of the following main layers: (i) a nucleation layer; (ii) a transition layer; (iii) a carbon-doped buffer layer; (iv) an unintentionally doped GaN channel layer; and (v) an AlGaN barrier layer. In some special cases, the C-doped buffer layer and the UID GaN layer can be modified by introducing a small amount of aluminum (<10%). This special case is generally referred to as the "back-barrier approach".

[0017] In the back barrier method, due to the presence of polarization charge, a two-dimensional hole gas (2DHG) is formed on the contact surface between the GaN channel and the AlGaN buffer. The advantages of the AlGaN back barrier can be summarized as follows: (1) Positive shift in threshold voltage. Due to the presence of the back barrier, the threshold voltage can reach a higher positive value. (2) Reduced subthreshold leakage and short-channel effects under normal circumstances. (3) The presence of the two-dimensional hole gas is very beneficial for minimizing the dynamic effects (current collapse, dynamic RDSON) of GaN technology. The main disadvantage of the back barrier is that the 2DHG is actually floating. Thus, the holes will move to the left or right depending on the applied field, which will have a strong impact on the carrier density and field distribution in the device. The new technology proposed in this invention provides a technical solution to avoid or at least greatly reduce the floating of 2DHG.

[0018] This invention describes a new technique that can alleviate the aforementioned problems. In these embodiments, the source-connected pGaN layer can be used to connect the two-dimensional hole gas formed at the bottom of the back barrier, thereby preventing the holes from remaining in a floating state. A strong hole channel maintained at a fixed source potential has advantages in optimizing the dynamic effects of GaN technology for power and RF applications. Specifically, a trench can be formed on the source side of the power device before gate formation, and this trench is filled with a p-type doped GaN layer during the subsequent growth of the p-GaN layer required for the gate module. Besides the details of the process flow, a key factor for successful implementation is the complete activation of the p-type GaN layer inside the deep trench, for example, by appropriate activation of the dopant element (Mg in this case) through dedicated process steps such as annealing.

[0019] A key element in successfully activating p-type dopants is to create one or more hollow cavities in the p-type doped region to form escape channels for hydrogen atoms, which are formed during the dopant activation of the p-type doped region in the process of manufacturing semiconductor devices.

[0020] Successful activation of Mg doped in GaN LEDs makes the manufacture and commercialization of blue LEDs possible. The efficient activation of dopants in deep trenches proposed in this invention is of great significance for all future vertical and semi-vertical power MOSFETs employing GaN technology.

[0021] According to a first aspect, the present invention relates to a semiconductor device. The semiconductor device includes: a semiconductor substrate; an aluminum gallium nitride (AlGaN) back barrier layer formed above the semiconductor substrate; and a GaN channel layer formed on the AlGaN back barrier layer, wherein a two-dimensional hole gas (2D hole) is present. A two-dimensional hole gas (2DHG) is formed on the contact surface between the GaN channel layer and the AlGaN back barrier layer; a p-type doped region is formed above the semiconductor substrate and adjacent to the GaN channel layer and the AlGaN back barrier layer, wherein the p-type doped region has a top surface and a bottom surface opposite to the top surface, the p-type doped region is used to provide ohmic contact for the two-dimensional hole gas formed on the contact surface between the GaN channel layer and the AlGaN back barrier layer; the p-type doped region includes magnesium as a p-type dopant; the p-type doped region includes one or more hollow cavities extending from the top surface of the p-type doped region; the one or more hollow cavities are used to form escape channels for hydrogen atoms, wherein the hydrogen atoms are formed when the p-type doped region is doped during the fabrication of the semiconductor device.

[0022] This hollow-cavity semiconductor device provides a means to achieve highly efficient dopant activation (specifically within deep trenches). It can be combined with p-type deep trenches connecting the source to a two-dimensional hole gas (2DHG). This GaN semiconductor device minimizes dynamic effects and current collapse, which remain major challenges in the successful development of GaN technology for RF and power applications. It is also suitable for realizing vertical GaN power transistors, as their operation requires a deeply buried p-type doped region.

[0023] The p-type doped region can optionally include dopants other than magnesium (Mg) or a combination of magnesium and other dopants. However, Mg is currently the most widely used p-type dopant. Ca, Zn, and Be can also be used optionally.

[0024] In one exemplary implementation of the semiconductor device, the one or more hollow cavities are filled with air or gas. Therefore, since hydrogen can use air or gas as an escape medium, an optimal escape path can be provided for the generated hydrogen. From an electrical perspective, any dielectric material can be used, such as SiO2, high-k materials, etc. However, air facilitates the escape of H. Therefore, air as an alternative is only a suboptimal solution.

[0025] In one exemplary implementation of the semiconductor device, the one or more hollow cavities are open to the environment of the semiconductor device. The escape channels are well-connected to the environment to allow the generated hydrogen to escape in an optimal manner. These hollow cavities are not only open to the atmosphere during the manufacturing process of the semiconductor device. Alternatively, these hollow cavities can be closed and used as escape chambers or storage chambers for the generated hydrogen.

[0026] In one exemplary implementation of the semiconductor device, the dopant activation of the p-type doped region during the fabrication of the semiconductor device includes thermal annealing, wherein the hydrogen atoms are released through the thermal annealing. By applying thermal annealing, dopant activation can be achieved efficiently.

[0027] In one exemplary implementation of the semiconductor device, the dopant activation dissociation of the magnesium-hydrogen complex formed in the p-type doped region releases hydrogen and electroactivates magnesium. By dissociating the magnesium-hydrogen complex, magnesium can be released efficiently, thus providing a highly doped region. The semiconductor device described above can be a gallium-nitride (GaN) semiconductor device, etc. The p-type doped region 101 can form a p-type doped GaN region, etc.

[0028] In one exemplary implementation of the semiconductor device, the activation energy for dopant activation of the p-type doped region is in the range of 160 meV to 200 meV. At this activation energy, magnesium can be released efficiently, thus providing a highly doped region in the semiconductor device.

[0029] In one exemplary implementation of the semiconductor device, the p-type doped region includes one or more side surfaces formed between the top and bottom surfaces of the p-type doped region; at least one of the one or more hollow cavities is formed on the one or more side surfaces of the p-type doped region. The hollow cavities can be formed on the side surfaces of the p-type doped region; these side surfaces can be easily connected to the environment, thereby efficiently releasing the generated hydrogen.

[0030] In one exemplary implementation of the semiconductor device, at least one of the one or more hollow cavities is formed at the center of the p-type doped region. Numerous contact areas exist between the hollow cavity and the p-type doped region, thereby enabling efficient release of hydrogen from the p-type doped region.

[0031] In one exemplary implementation of the semiconductor device, at least one of the one or more hollow cavities extends from the top surface of the p-type doped region to the bottom surface. The hollow cavity extends deep into the p-type doped region, thereby efficiently transferring hydrogen into the hollow cavity.

[0032] In one exemplary implementation of the semiconductor device, at least one of the one or more hollow cavities extends from the top surface of the p-type doped region into the interior of the p-type doped region. Hydrogen atoms can be efficiently released through the top surface of the p-type doped region.

[0033] In one example, one or more hollow cavities may reach the bottom surface of the p-type doped region. In another example, one or more hollow cavities may not reach the bottom surface of the p-type doped region, in which case the bottom of the hollow cavity may be formed by the p-type doped region.

[0034] In one exemplary implementation of the semiconductor device, the semiconductor device includes: a top surface and a bottom surface opposite to the top surface; and a trench formed on the top surface of the semiconductor device, wherein the trench is filled with a p-type doped material, the p-type doped material forming the p-type doped region. Therefore, the dopant region can be efficiently activated in the trench, specifically in a deep trench.

[0035] In one exemplary implementation of the semiconductor device, the semiconductor device includes: a source electrode, with source fingers formed on the top surface of the semiconductor device, wherein the source fingers include two source finger sides and a center between the two source finger sides, and one or more hollow cavities are formed along the source finger sides or along the center of the source finger. A large contact area can be provided between the hollow cavities and the source fingers, thereby enabling the efficient transfer of hydrogen atoms to the environment.

[0036] In one exemplary implementation of the semiconductor device, the one or more hollow cavities are formed continuously or discontinuously along the two source finger sides or along the center of the source finger. This provides flexible design options.

[0037] In one exemplary implementation of the semiconductor device, the p-type doped region connects the 2DHG to the source to prevent the 2DHG from floating. Therefore, 2DHG floating can be effectively prevented.

[0038] The aforementioned semiconductor device may include a transition layer formed on a semiconductor substrate. An AlGaN back barrier layer may be formed on the transition layer. The aforementioned semiconductor device may include an AlGaN barrier layer formed on a GaN channel layer. A two-dimensional electron gas (2DEG) may be formed on the contact surface between the GaN channel layer and the AlGaN barrier layer. The aforementioned semiconductor device may include a p-type doped GaN layer formed on the AlGaN barrier layer.

[0039] A p-type doped GaN layer can form a second p-type doped region in a semiconductor device. This second p-type doped region may include one or more other hollow cavities extending from the top surface of the second p-type doped region into the second p-type doped region.

[0040] According to a second aspect, the present invention relates to a method for manufacturing a semiconductor device. The method includes: forming a semiconductor substrate; forming an aluminum gallium-nitride (AlGaN) back barrier layer over the semiconductor substrate; and forming a GaN channel layer on the AlGaN back barrier layer, wherein a two-dimensional hole gas (2D hole gas) is formed. A two-dimensional hole gas (2DHG) is formed on the contact surface between the GaN channel layer and the AlGaN back barrier layer; a p-type doped region is formed above the semiconductor substrate and immediately adjacent to the GaN channel layer and the AlGaN back barrier layer, wherein the p-type doped region has a top surface and a bottom surface opposite to the top surface, the p-type doped region provides an ohmic contact for the two-dimensional hole gas formed on the contact surface between the GaN channel layer and the AlGaN back barrier layer, the p-type doped region including magnesium as a p-type dopant; one or more hollow cavities are formed in the p-type doped region, wherein the one or more hollow cavities extend from the top surface of the p-type doped region; the p-type doped region is activated by a dopant, wherein the dopant activation forms hydrogen atoms; the hydrogen atoms are released through the one or more hollow cavities.

[0041] Therefore, a semiconductor device capable of achieving efficient dopant activation (specifically in deep trenches) can be efficiently manufactured. This method can be combined with the fabrication of p-type deep trenches connecting the source junctions of a two-dimensional hole gas (2DHG). This fabrication method minimizes dynamic effects and current collapse, which remain major challenges in the successful development of GaN technology for RF and power applications. This approach is also suitable for fabricating vertical GaN power transistors, as the operation of such devices requires deeply buried p-type doped regions.

[0042] The aforementioned p-type doped region may optionally include other dopants besides magnesium or a combination of magnesium and other dopants. Attached Figure Description

[0043] Other embodiments of the present invention will be described in conjunction with the following drawings, in which:

[0044] Figure 1a This is a schematic cross-sectional view of a first embodiment of the semiconductor device 100 provided by the present invention;

[0045] Figure 1b This is a schematic cross-sectional view of a second embodiment of the semiconductor device 100 provided by the present invention;

[0046] Figure 1c This is a schematic cross-sectional view of a third embodiment of the semiconductor device 100 provided by the present invention;

[0047] Figure 2 These are three top side views of three other embodiments of the semiconductor device 100 provided by the present invention. Detailed Implementation

[0048] In the following detailed description, reference is made to the accompanying drawings, which form a part of this specification, illustrating specific aspects in which the invention can be practiced. It should be understood that other aspects may be utilized, and structural or logical changes may be made, without departing from the scope of the invention. Therefore, the following detailed description should not be construed in a limiting sense, and the scope of the invention is defined by the appended claims.

[0049] It should be understood that interpretations relating to the described methods may also apply to corresponding devices or systems used to perform the methods, and vice versa. For example, if a specific method step is described, the corresponding device may include units for performing the described method steps, even if such units are not illustrated or depicted in detail in the figures. Furthermore, it should be understood that features of the various exemplary aspects described herein may be combined with each other unless otherwise explicitly stated.

[0050] Figure 1a This is a schematic cross-sectional view of the first embodiment of the semiconductor device 100 provided by the present invention.

[0051] like Figure 1a As shown, trench 103 is formed, specifically a deep trench 103, which is then filled with a p-type doped material (e.g., magnesium-doped GaN). The main purpose of this doped region is to enable electrical contact between the originally floating two-dimensional hole gas formed on the contact surface between the GaN channel and the underlying carbon-doped buffer zone.

[0052] Because the dopant activation ability of p-type dopants in deep trenches is limited, a dopant is introduced. Figure 1a One or more hollow cavities 102, such as air gaps, are shown. These hollow cavities 102 or air gaps may be formed on one side of the trench (e.g., the left or right side) or in the center of the trench 103. The primary purpose of these openings is to create an escape path for hydrogen atoms so that hydrogen can escape during the annealing step, after the Mg-H complex breaks down, thereby enabling better dopant activation in the deep trench.

[0053] Figure 1a The semiconductor device 100 shown includes: a semiconductor substrate 110; an aluminum gallium-nitride (AlGaN) back barrier layer 121 formed above the semiconductor substrate 110; a GaN channel layer 122 formed on the AlGaN back barrier layer 121, wherein two-dimensional hole gas (2DHG) is formed on a contact surface 123 between the GaN channel layer 122 and the AlGaN back barrier layer 121; and a p-type doped region 101 formed above the semiconductor substrate 110 and adjacent to the GaN channel layer 122 and the AlGaN back barrier layer 121. The p-type doped region 101 has a top surface 101a and a bottom surface 101b opposite to the top surface 101a. The p-type doped region 101 provides ohmic contact for the two-dimensional hole gas formed on the contact surface 123 between the GaN channel layer 122 and the AlGaN back barrier layer 121.

[0054] The p-type doped region 101 may include magnesium as a p-type dopant. The p-type doped region 101 may optionally include other dopants besides magnesium (Mg) or a combination of magnesium and other dopants. However, Mg is the most widely used p-type dopant element. Optionally, Ca, Zn, and Be may also be used.

[0055] like Figure 1a As shown, the p-type doped region 101 includes one or more hollow cavities 102 extending from the top surface 101a of the p-type doped region 101.

[0056] One or more hollow cavities 102 are used to form escape channels for hydrogen atoms, wherein the hydrogen atoms are formed during the dopant activation of the p-type doped region 101 during the fabrication of the semiconductor device 100.

[0057] One or more hollow cavities 102 can be filled with air or gas. From an electrical point of view, any dielectric material can be used, such as SiO2, high-k, etc. However, air allows hydrogen to escape easily. Therefore, air as an alternative is only a suboptimal technical solution.

[0058] One or more hollow cavities 102 may be open to the environment of the semiconductor device 100. The hollow cavity 102 may be open to the atmosphere not only during the manufacturing process of the semiconductor device 100. Alternatively, the hollow cavity 102 may be closed and used as an escape chamber or storage chamber for the generated hydrogen.

[0059] Activating the p-type doped region 101 with dopant during the manufacturing of semiconductor device 100 may include thermal annealing, in which hydrogen atoms are released through thermal annealing.

[0060] Dopant activation of the p-type doped region 101 can dissociate the magnesium-hydrogen complex formed in the p-type doped region 101, thereby releasing hydrogen and electroactivating magnesium.

[0061] Semiconductor device 100 can be a gallium-nitride (GaN) semiconductor device, etc. The p-type doped region 101 can form a p-type doped GaN region, etc.

[0062] The activation energy used to activate the p-type doped region 101 can be in the range of 160 meV to 200 meV, etc. Other ranges can also be used, such as between 150 meV and 210 meV, between 140 meV and 220 meV, between 110 meV and 250 meV, between 170 meV and 190 meV, or between 165 meV and 195 meV, etc.

[0063] like Figure 1a As shown, the p-type doped region 101 may include one or more side surfaces 101c formed between the top surface 101a and the bottom surface 101b of the p-type doped region 101. Figure 1b As shown, at least one of the hollow cavities 102 may be formed on one or more sides 101c of the p-type doped region 101.

[0064] like Figure 1a As shown, at least one of the hollow cavities 102 may be formed at the center of the p-type doped region 101.

[0065] In another embodiment, at least one of the hollow cavities 102 may be formed on one or more sides 101c of the p-type doped region 101, and at least one of the hollow cavities 102 may be formed at the center of the p-type doped region 101.

[0066] For example, such as Figure 1b and Figure 1c As shown, at least one of the hollow cavities 102 may extend from at least the top surface 101a of the p-type doped region 101 to the bottom surface 101b.

[0067] For example, such as Figure 1a , Figure 1b , Figure 1c As shown, at least one of the hollow cavities 102 can extend from the top surface 101a of the p-type doped region 101 to the interior of the p-type doped region 101.

[0068] In one example, one or more hollow cavities 102 may reach the bottom surface 101b of the p-type doped region 101. In another example, one or more hollow cavities 102 may not reach the bottom surface 101b of the p-type doped region 101, in which case the bottom of the hollow cavity 102 may be formed by the p-type doped region 101.

[0069] Semiconductor device 100 may include: a top surface 100a and a bottom surface 100b opposite to the top surface 100a; and a trench 103 formed on the top surface 100a of semiconductor device 100. For example... Figure 1a , Figure 1b and Figure 1c As shown, trench 103 can be filled with p-type doped material. The p-type doped material forms p-type doped region 101.

[0070] For example, such as Figure 2 As shown, the semiconductor device 100 may include a source 152 on the top surface 100a of the semiconductor device 100, where a source finger is formed. For example, as Figure 2 As shown, the source finger may include two source finger sides 152a, 152b and a center 152c between the two source finger sides 152a, 152b. For example, as Figure 2 As shown, one or more hollow cavities 102 may be formed along the source finger side 152a, 152b or along the source finger center 152c.

[0071] For example, such as Figure 2 As shown, one or more hollow cavities 102 can be formed continuously or discontinuously along the two source finger sides 152a, 152b or along the source finger center 152c.

[0072] The p-type doped region 101 can connect 2DHG to the source 152 to prevent 2DHG from floating.

[0073] like Figure 1a As shown, the semiconductor device 100 may include a transition layer 111 formed on the semiconductor substrate 110. An AlGaN back barrier layer 121 may be formed on the transition layer 111.

[0074] Semiconductor device 100 may include an AlGaN barrier layer 130 formed on GaN channel layer 122. For example... Figure 1aAs shown, a two-dimensional electron gas (2DEG) can be formed on the contact surface 124 between the GaN channel layer 122 and the AlGaN barrier layer 130.

[0075] The first ohmic contact 152 of the two-dimensional electron gas can be used as a source contact, while the second ohmic contact 153 of the two-dimensional electron gas can be used as a drain contact. The passivation layer 160 can cover the p-type doped region 101, the AlGaN barrier layer 130, and the two ohmic contacts 152 and 153 on the top surface 100a of the semiconductor device 100. The hollow cavity 102 can extend through the passivation layer 160. The passivation layer 160 can be a high-k dielectric, for example, made of silicon nitride (SiN), aluminum nitride (AlN), silicon oxide (SiO2), or any combination thereof.

[0076] like Figure 1a As shown, the semiconductor device 100 may include a p-type doped GaN layer 140 formed on the AlGaN barrier layer 130. The p-type doped GaN layer 140 may form a second p-type doped region of the semiconductor device 100. The second p-type doped region may include a region extending from the top surface of the second p-type doped region to the second p-type doped region (…). Figure 1a One or more other hollow cavities 102 (not shown). A p-type doped GaN layer 140 may extend through a passivation layer 160. A gate metal 151 may be placed on top of the p-type doped GaN layer 140.

[0077] Figure 1b This is a schematic cross-sectional view of a second embodiment of the semiconductor device 100 provided by the present invention.

[0078] Figure 1b The structure of the semiconductor device 100 shown is in conjunction with the above. Figure 1a The semiconductor device 100 described has the same structure. One difference between the second embodiment and the first embodiment is that the hollow cavity 102 is not placed at the center of the p-type doped region 101, but is placed on the sidewall 101c of the p-type doped region 101.

[0079] Another difference between the second embodiment and the first embodiment is that at least one hollow cavity 102 extends downward from the top surface 101a of the p-type doped region 101 to the bottom surface 101b of the p-type doped region 101. In this case, the bottom of the at least one hollow cavity 102 can be formed by an AlGaN back barrier layer 121.

[0080] Figure 1c This is a schematic cross-sectional view of a third embodiment of the semiconductor device 100 provided by the present invention.

[0081] Figure 1c The structure of the semiconductor device 100 shown is in conjunction with the above. Figure 1a The semiconductor device 100 described has the same structure. One difference between the third embodiment and the first embodiment is that at least one hollow cavity 102 extends from the top surface 101a of the p-type doped region 101 to the bottom surface 101b of the p-type doped region 101, and downwards to the AlGaN back barrier layer 121. In this case, the bottom of the at least one hollow cavity 102 and the lower portion of the sidewalls (depending on the depth of the at least one hollow cavity 102) can be formed by the AlGaN back barrier layer 121.

[0082] Figure 2 These are three top side views of three other embodiments of the semiconductor device 100 provided by the present invention.

[0083] Figure 2 The structure of the semiconductor device 100 shown is in conjunction with the above. Figure 1a The semiconductor device 100 described has the same structure. Different structures of the hollow cavity 102 are shown in these three top side views.

[0084] Semiconductor device 100 may include a source 152, a gate / drain 151, and a drain 153. For example... Figure 2 As shown in the three embodiments, the shape of the source 152 can be different.

[0085] Source 152 can be formed on the top surface 100a of semiconductor device 100. For example... Figure 2 As shown, the source finger may include two source finger sides 152a, 152b and a center 152c between the two source finger sides 152a, 152b.

[0086] like Figure 2 As shown, one or more hollow cavities 102 may be formed along the source finger side 152a, 152b or along the source finger center 152c.

[0087] One or more hollow cavities 102 may be formed continuously or discontinuously along the two source finger sides 152a, 152b or along the source finger center 152c. Figure 2 In the diagram, the top and middle figures show a continuously formed hollow cavity 102, while the bottom figure shows a discontinuously formed hollow cavity 102. In this embodiment, the hollow cavity 102 can be formed into a regular pattern. It is understood that the hollow cavity can also be formed into an irregular pattern, or even a random pattern.

[0088] As described above, the hollow cavity 102 can be inserted along the source finger side 152a, 152b or along the source finger center 152c. The hollow cavity 102 can be continuous or discontinuous, for example, interrupted, for example, composed of more than one individual hollow cavity 102 connected in series.

[0089] The present invention also provides a method for manufacturing Figure 1a , Figure 1b , Figure 1c and Figure 2 The method of the semiconductor device 100 shown.

[0090] This method includes the following steps:

[0091] Forming a semiconductor substrate 110;

[0092] An aluminum gallium nitride (AlGaN) back barrier layer 121 is formed above the semiconductor substrate 110;

[0093] A GaN channel layer (122) is formed on the AlGaN back barrier layer 121, wherein a two-dimensional hole gas (2DHG) is formed on the contact surface 123 between the GaN channel layer 122 and the AlGaN back barrier layer 121, for example, as described above. Figure 1a The above;

[0094] A p-type doped region 101 is formed above and immediately adjacent to the GaN channel layer 122 and the AlGaN back barrier layer 121 on the semiconductor substrate 110. The p-type doped region has a top surface 101a and a bottom surface 101b opposite to the top surface 101a. The p-type doped region 101 provides ohmic contact for two-dimensional hole gas formed on the contact surface between the GaN channel layer 122 and the AlGaN back barrier layer 121. The p-type doped region 101 may include magnesium as a p-type dopant, for example, as described above in conjunction with... Figure 1a The above;

[0095] One or more hollow cavities 102 are formed in the p-type doped region 101, wherein the one or more hollow cavities 102 extend from the top surface 101a of the p-type doped region 101, for example, as described above. Figure 1a The above;

[0096] The p-type doped region 101 is activated by a dopant, wherein the activation of the dopant leads to the formation of hydrogen atoms;

[0097] Hydrogen atoms are released through one or more hollow cavities 102, for example, as described above. Figure 1a As stated above.

[0098] The p-type doped region 101 may optionally include dopants other than magnesium or a combination of magnesium and other dopants.

[0099] While specific features or aspects of the invention may have been disclosed in combination with only one of several implementations, such features or aspects may be combined with one or more features or aspects of other implementations, provided that they are necessary or advantageous for any given or particular application. Furthermore, to a certain extent, the terms “comprising,” “having,” “possessing,” or other variations of these words are used in the detailed description or claims; such terms are similar to the term “comprising” and both indicate inclusion. Similarly, the terms “exemplary” and “for example” are used only as examples and not as best or most preferred. The terms “coupled” and “connected,” as well as their derivatives, may be used. It should be understood that these terms may be used to indicate that two elements cooperate or interact with each other, whether they are in direct physical or electrical contact, or whether they are not in direct contact with each other.

[0100] While specific aspects have been illustrated and described herein, those skilled in the art will understand that various alternatives and / or equivalent implementations may replace the specific aspects shown and described without departing from the scope of the invention. This application is intended to cover any modifications or alterations to the specific aspects discussed herein.

[0101] Although the elements in the above claims are listed in a specific order using corresponding labels, these elements are not necessarily limited to being implemented in that specific order unless the description of the claims otherwise implies a specific order for implementing some or all of these elements.

[0102] Based on the above guidance, many alternatives, modifications, and variations will be apparent to those skilled in the art. Of course, those skilled in the art will readily recognize that numerous other applications of the invention exist besides those described herein. Although the invention has been described in conjunction with one or more specific embodiments, those skilled in the art will recognize that many changes can be made to the invention without departing from its scope. Therefore, it should be understood that the invention can be practiced in ways other than those specifically described herein, as long as it remains within the scope of the appended claims and their equivalents.

Claims

1. A semiconductor device (100), characterized in that, The semiconductor device (100) includes: Semiconductor substrate (110); An aluminum gallium nitride (AlGaN) back barrier layer (121) is formed on the semiconductor substrate (110). A GaN channel layer (122) is formed on the AlGaN back barrier layer (121). Two-dimensional hole gas (2DHG) is formed on the contact surface (123) between the GaN channel layer (122) and the AlGaN back barrier layer (121); A p-type doped region (101) is formed above the semiconductor substrate (110) and adjacent to the GaN channel layer (122) and the AlGaN back barrier layer (121), wherein the p-type doped region (101) has a top surface (101a) and a bottom surface (101b) opposite to the top surface (101a), and the p-type doped region (101) is used to provide an ohmic contact for the two-dimensional hole gas formed on the contact surface (123) between the GaN channel layer (122) and the AlGaN back barrier layer (121). The p-type doped region (101) includes magnesium as a p-type dopant. The p-type doped region (101) includes one or more hollow cavities (102) extending from the top surface (101a) of the p-type doped region (101). The one or more hollow cavities (102) are used to form escape channels for hydrogen atoms, wherein the hydrogen atoms are formed during the dopant activation of the p-type doped region (101) during the fabrication of the semiconductor device (100).

2. The semiconductor device (100) according to claim 1, characterized in that, The one or more hollow cavities (102) are filled with air or gas.

3. The semiconductor device (100) according to claim 1 or 2, characterized in that, The one or more hollow cavities (102) are open to the environment of the semiconductor device (100).

4. The semiconductor device (100) according to claim 1 or 2 above, characterized in that, The dopant activation of the p-type doped region (101) during the manufacturing of the semiconductor device (100) includes thermal annealing, wherein the hydrogen atoms are released through the thermal annealing.

5. The semiconductor device (100) according to claim 1 or 2 above, characterized in that, The dopant activation and dissociation of the p-type doped region (101) forms a magnesium-hydrogen complex in the p-type doped region, thereby releasing hydrogen and electroactivating magnesium.

6. The semiconductor device (100) according to claim 1 or 2 above, characterized in that, The activation energy used to activate the p-type doped region (101) is in the range of 160 meV and 200 meV.

7. The semiconductor device (100) according to claim 1 or 2 above, characterized in that, The p-type doped region (101) includes one or more side surfaces (101c) formed between the top surface (101a) and the bottom surface (101b) of the p-type doped region (101). At least one of the hollow cavities (102) is formed on the one or more sides (101c) of the p-type doped region (101).

8. The semiconductor device (100) according to claim 1 or 2 above, characterized in that, At least one of the hollow cavities (102) is formed at the center of the p-type doped region (101).

9. The semiconductor device (100) according to claim 1 or 2 above, characterized in that, At least one of the hollow cavities (102) extends from the top surface (101a) of the p-type doped region (101) to the bottom surface (101b).

10. The semiconductor device (100) according to claim 1 or 2 above, characterized in that, At least one of the one or more hollow cavities (102) extends from the top surface (101a) of the p-type doped region (101) into the interior of the p-type doped region (101).

11. The semiconductor device (100) according to claim 1 or 2 above, characterized in that, The semiconductor device (100) includes: Top surface (100a) and bottom surface (100b) opposite to the top surface (100a); A trench (103) is formed on the top surface (100a) of the semiconductor device (100), wherein the trench (103) is filled with a p-type doped material. The p-type doped material forms the p-type doped region (101).

12. The semiconductor device (100) according to claim 11, characterized in that, The semiconductor device (100) includes: Source (152), a source finger is formed on the top surface (100a) of the semiconductor device (100), wherein the source finger includes two source finger sides (152a, 152b) and a center (152c) between the two source finger sides (152a, 152b). The one or more hollow cavities (102) are formed along the source finger side (152a, 152b) or along the source finger center (152c).

13. The semiconductor device (100) according to claim 12, characterized in that, The one or more hollow cavities (102) are formed continuously or discontinuously along the two source finger sides (152a, 152b) or along the source finger center (152c).

14. The semiconductor device (100) according to claim 1 or 2 above, characterized in that, The p-type doped region (101) connects the 2DHG to the source (152) to prevent the 2DHG from floating.

15. A method for manufacturing a semiconductor device (100), characterized in that, The method includes: Forming a semiconductor substrate (110); An aluminum gallium nitride (AlGaN) back barrier layer (121) is formed over the semiconductor substrate (110). A GaN channel layer (122) is formed on the AlGaN back barrier layer (121). Two-dimensional hole gas (2DHG) is formed on the contact surface (123) between the GaN channel layer (122) and the AlGaN back barrier layer (121); A p-type doped region (101) is formed above and immediately adjacent to the GaN channel layer (122) and the AlGaN back barrier layer (121) on the semiconductor substrate (110). The p-type doped region has a top surface (101a) and a bottom surface (101b) opposite to the top surface (101a). The p-type doped region (101) provides an ohmic contact for the two-dimensional hole gas formed on the contact surface between the GaN channel layer (122) and the AlGaN back barrier layer (121). The p-type doped region (101) includes magnesium as a p-type dopant; One or more hollow cavities (102) are formed in the p-type doped region (101), wherein the one or more hollow cavities (102) extend from the top surface (101a) of the p-type doped region (101); The p-type doped region (101) is activated by a dopant, wherein the activation of the dopant leads to the formation of hydrogen atoms; The hydrogen atoms are released through one or more hollow cavities (102).

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