Single-gate bidirectional switching device and preparation method thereof

Abstract

The invention provides a single-gate bidirectional switching device and a preparation method thereof, the device comprises a substrate, a first gallium oxide layer, a second gallium oxide layer and a semiconductor material layer which are stacked in sequence along a stacking direction, the device further comprises a first electrode, a second electrode and a gate, the semiconductor material layer covers part of the second gallium oxide layer, and the first electrode covers the second gallium oxide layer. The first electrode and the second electrode are located on the side, away from the first gallium oxide layer, of the second gallium oxide layer, and the gate is located on the side, away from the second gallium oxide layer, of the semiconductor material layer, covers part of the semiconductor material layer and is located between the first electrode and the second electrode. The second gallium oxide layer and the semiconductor material layer between the first electrode and the grid electrode are used for forming a first heterogeneous super-junction voltage-withstanding region, and the second gallium oxide layer and the semiconductor material layer between the second electrode and the grid electrode are used for forming a second heterogeneous super-junction voltage-withstanding region. According to the invention, the control complexity of the device is reduced, the device can be applied more easily, and the control logic of the bidirectional switching device is greatly simplified.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor, in particular to a single-gate bidirectional switch device and a preparation method. BACKGROUND

[0002] Bidirectional switch devices have important applications in the fields of AC-AC conversion, three-phase rectification / inversion, and micro-inverters. In traditional silicon (Si) based power device applications, to achieve the function of bidirectional switch devices, four discrete devices are needed to achieve the function through a "two series two parallel" method, which increases the cost and complexity of the system. In wide bandgap semiconductor materials, gallium oxide (Ga2O3) has a bandgap of 4.8eV, an ideal breakdown field strength of 8MV / cm, and a BFOM value of up to 3400, which is about 4 times that of gallium nitride (GaN) and 10 times that of silicon carbide (SiC). Therefore, in today's power electronic applications with higher power density and lower power consumption requirements, Ga2O3 materials have more significant research significance and more broad market application prospects. If a bidirectional switch device based on Ga2O3 material can be made, it will have important application value.

[0003] Therefore, there is an urgent need for a single-gate bidirectional switch device. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a single-gate bidirectional switch device and a preparation method, which reduces the control complexity of the device, makes the device easier to apply, and greatly simplifies the control logic of the bidirectional switch device. The specific scheme is as follows:

[0005] In one aspect, the present application provides a single-gate bidirectional switch device, comprising:

[0006] a substrate, a first gallium oxide layer, a second gallium oxide layer and a semiconductor material layer stacked in sequence along a stacking direction; the semiconductor material layer covers part of the second gallium oxide layer, the second gallium oxide layer has a first conductivity type, and the semiconductor material layer has a second conductivity type;

[0007] a first electrode and a second electrode located on the side of the second gallium oxide layer away from the first gallium oxide layer, the first electrode and the second electrode are both source electrodes or both drain electrodes;

[0008] a gate electrode located on the side of the semiconductor material layer away from the second gallium oxide layer, the gate electrode covers part of the semiconductor material layer, and the gate electrode is located between the first electrode and the second electrode;

[0009] The second gallium oxide layer and the semiconductor material layer between the first electrode and the gate electrode are used to form a first hetero super junction voltage resistance region, and the second gallium oxide layer and the semiconductor material layer between the second electrode and the gate electrode are used to form a second hetero super junction voltage resistance region.

[0010] Optionally, the semiconductor material layer between the first electrode and the gate electrode has a first width, and the semiconductor material layer between the second electrode and the gate electrode has a second width.

[0011] The first width is equal to the second width, or the width difference between the first width and the second width is greater than a preset difference.

[0012] Optionally, the semiconductor material layer includes a first part and a second part separated from each other, the gate electrode covers part of the first part, and covers part of the second part.

[0013] Optionally, the semiconductor material layer includes a third part and a fourth part separated from each other, the third part is between the first electrode and the fourth part, and the gate electrode covers part of the fourth part.

[0014] The third part, the fourth part and the second gallium oxide layer between the first electrode and the gate electrode are used to form the first hetero super junction voltage resistance region, and the second gallium oxide layer and the fourth part between the second electrode and the gate electrode are used to form the second hetero super junction voltage resistance region.

[0015] Optionally, the semiconductor material layer further includes a fifth part separated from the fourth part, and the fifth part is between the second electrode and the fourth part.

[0016] The fifth part, the second gallium oxide layer and the fourth part between the second electrode and the gate electrode are used to form the second hetero super junction voltage resistance region.

[0017] Optionally, the semiconductor material layer is a complete film layer between the first electrode and the second electrode.

[0018] Optionally, the semiconductor material layer includes a transverse strip structure and a longitudinal strip structure, the transverse strip structure extends along a connecting line between the first electrode and the second electrode, and the longitudinal strip structure extends in the same direction as the gate electrode.

[0019] The longitudinal strip structure and the transverse strip structure are arranged in cross, and the longitudinal strip structure and the transverse strip structure arranged in cross have cross contact points.

[0020] Optionally, a contact layer is further included between the gate and the semiconductor material layer, the contact layer has the second conductivity type, and a doping concentration in the contact layer is greater than a doping concentration in the semiconductor material layer.

[0021] Optionally, a material of the semiconductor material layer is nickel oxide, gallium nitride, or iridium gallium oxide.

[0022] In another aspect, the embodiments of the present application further provide a preparation method of a single-gate bidirectional switch device, the method comprising:

[0023] forming a semiconductor material layer on a gallium oxide epitaxial layer, the gallium oxide epitaxial layer comprising a substrate, a first gallium oxide layer, and a second gallium oxide layer which are sequentially stacked, the semiconductor material layer exposing the second gallium oxide layer at least at two side edge regions; the second gallium oxide layer has a first conductivity type, and the semiconductor material layer has a second conductivity type;

[0024] forming a first electrode and a second electrode on the second gallium oxide layer at the two side edge regions, and forming a gate on the semiconductor material layer, the first electrode and the second electrode are either source electrodes or drain electrodes, the gate covers part of the semiconductor material layer, and the gate is located between the first electrode and the second electrode; the second gallium oxide layer and the semiconductor material layer between the first electrode and the gate are used to form a first hetero super-junction voltage-resisting region, and the second gallium oxide layer and the semiconductor material layer between the second electrode and the gate are used to form a second hetero super-junction voltage-resisting region.

[0025] In another aspect, the embodiments of the present application further provide a single-gate bidirectional switch device, the single-gate bidirectional switch device comprising: a substrate, a buffer layer, a channel layer, a barrier layer, a semiconductor material layer, a first electrode, a second electrode, and a gate;

[0026] The substrate, the buffer layer, the channel layer, the barrier layer, and the semiconductor material layer are sequentially stacked, the gate is arranged on a side of the semiconductor material layer away from the substrate, the first electrode and the second electrode are arranged on a side of the barrier layer, and the gate is located between the first electrode and the second electrode.

[0027] The barrier layer and the channel layer have a first conductivity type, and the semiconductor material layer has a second conductivity type.

[0028] Optionally, the channel layer is a GaO channel layer, and the barrier layer is an AlGaO barrier layer.

[0029] Or, the channel layer is a GaN channel layer, and the barrier layer is an AlGaN barrier layer.

[0030] The embodiment of the present application provides a single-gate bidirectional switch device and a preparation method, the device comprises a substrate, a first gallium oxide layer, a second gallium oxide layer and a semiconductor material layer which are sequentially stacked along a stacking direction, and further comprises a first electrode, a second electrode and a gate electrode, the semiconductor material layer covers part of the second gallium oxide layer, the second gallium oxide layer has a first conductive type, and the semiconductor material layer has a second conductive type, so that the semiconductor material layer and the second gallium oxide layer can form a heterojunction, the first electrode and the second electrode are located on a side of the second gallium oxide layer away from the first gallium oxide layer, the first electrode and the second electrode are both source electrodes or both drain electrodes, the gate electrode is located on a side of the semiconductor material layer away from the second gallium oxide layer, the gate electrode covers part of the semiconductor material layer, and the gate electrode is located between the first electrode and the second electrode. The second gallium oxide layer and the semiconductor material layer located between the first electrode and the gate electrode are used for forming a first heterojunction super-junction voltage-resisting area, so that high voltage resistance of one switch device is realized, and the second gallium oxide layer and the semiconductor material layer located between the second electrode and the gate electrode are used for forming a second heterojunction super-junction voltage-resisting area, so that high voltage resistance of another switch device is realized. The present application adopts a single gate to control a double switch device, that is, both of the two switch devices are controlled through the same gate electrode, when the application scene is a medium-low voltage application scene such as 10V-100V, the gate electrode control can be more simple, the switch device can be turned on only by controlling the voltage of the single gate electrode, two gate electrodes do not need to be arranged for the double switch device, and two gate electrode signal driving controls do not need to be separately arranged, so that the device control complexity is reduced, the device can be more easily applied, and the control logic of the bidirectional switch device is greatly simplified. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0032] Figure 1 A three-dimensional schematic view of a single-gate bidirectional switch device provided by the embodiment of the present application is shown;

[0033] Figure 2 is shown in the direction of AA; Figure 1

[0034] Figures 3-8 A cross-sectional view of a single-gate bidirectional switch device provided by the embodiment of the present application is shown;

[0035] Figure 9 A top view of a single-gate bidirectional switch device provided by the embodiment of the present application is shown;

[0036] Figure 10 ​A cross-sectional view of a single-gate bidirectional switching device is shown.

[0037] Figure 11 A flowchart of a preparation method of a single-gate bidirectional switching device is shown.

[0038] Figures 12-16 A cross-sectional view of a single-gate bidirectional switching device is shown. DETAILED DESCRIPTION

[0039] To make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0040] In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present application, therefore the present application is not limited to the specific embodiments disclosed below.

[0041] Secondly, the present application is described in detail in combination with the schematic diagram, when the embodiments of the present application are described in detail, for the convenience of description, the cross-sectional view showing the structure of the device will be partially enlarged without the general proportion, and the schematic diagram is only an example, which should not limit the scope of protection of the present application herein. In addition, the three-dimensional spatial dimensions of length, width and depth should be included in actual manufacturing.

[0042] For the convenience of understanding, a single-gate bidirectional switching device provided by the embodiments of the present application is described in detail below with reference to the accompanying drawings.

[0043] Reference Figure 1 A three-dimensional schematic diagram of a single-gate bidirectional switching device provided by the embodiments of the present application is shown, Figure 2 is along Figure 1 the cross-sectional view in AA direction, Figure 2 The through hole 190 is not shown in the figure. The single-gate bidirectional switching device includes a substrate 110, a first gallium oxide layer 120, a second gallium oxide layer 130, a semiconductor material layer 140, a first electrode 151, a second electrode 152 and a gate 160.

[0044] Among them, the substrate 110, the first gallium oxide layer 120, the second gallium oxide layer 130 and the semiconductor material layer 140 are stacked in turn along the stacking direction, the stacking direction can be the vertical direction, the semiconductor material layer 140 does not cover all the second gallium oxide layer 130, only covers part of the second gallium oxide layer 130, and the semiconductor material layer 140 at least exposes the second gallium oxide layer 130 located in the two side edge regions.

[0045] The substrate 110 can be a semi-insulating gallium oxide substrate 110, a sapphire substrate 110 or a silicon substrate 110 for supporting the single-gate bidirectional switching device. The material of the first gallium oxide layer 120 is unintentionally doped (UID) gallium oxide. The thickness of the first gallium oxide layer 120 ranges from 10-5000 nm. The thickness of the second gallium oxide layer 130 can range from 50-200 nm.

[0046] The second gallium oxide layer 130 has a first conductivity type, and the semiconductor material layer 140 has a second conductivity type, the first conductivity type and the second conductivity type being opposite conductivity types, so as to form a heterojunction. The second gallium oxide layer 130 can serve as a channel layer of the device. As an example, when the first conductivity type is P-type, the second conductivity type is N-type, and when the first conductivity type is N-type, the second conductivity type is P-type. For ease of illustration, the first conductivity type is N-type and the second conductivity type is P-type in the following description.

[0047] In one possible implementation, the material of the semiconductor material layer 140 can be nickel oxide (NiO), gallium nitride (GaN) or iridium gallium oxide (a-(IrGa)2O3), so as to improve the selectivity of the semiconductor material layer 140 and prepare single-gate bidirectional switching devices with various characteristics. Each material will be described in detail below. As an example, the semiconductor material layer 140 with the second conductivity type can be P-type NiO, P-type GaN or P-type iridium gallium oxide. Of course, the semiconductor material layer 140 can also be other metal oxide layers. The thickness of the semiconductor material layer 140 can range from 10 nm to 200 nm, and further can range from 20 nm to 60 nm, so that when the device is in an off state and reverse working voltage, the charges in the semiconductor material layer 140 can be electrically neutralized and complementary to the charges in the second gallium oxide layer 130, achieving charge balance and constructing a lateral super-junction voltage-resistant structure, i.e., a hetero-super-junction voltage-resistant region, to ensure that the device can bear a higher voltage.

[0048] The first electrode 151 and the second electrode 152 are located on the side of the second gallium oxide layer 130 away from the first gallium oxide layer 120, for example, above the second gallium oxide layer 130 at the edge regions on both sides. The first electrode 151 and the second electrode 152 can both be source electrodes, in which case the single-gate bidirectional switching device is a common-drain device, or both can be drain electrodes, in which case the single-gate bidirectional switching device is a common-source device. The following description takes the example in which the first electrode 151 and the second electrode 152 are both drain electrodes. The material of the electrodes can be a Ti / Au stack or a Ni / Au stack.

[0049] The gate electrode 160 is located on the side of the semiconductor material layer 140 away from the second gallium oxide, for example, above the semiconductor material layer 140, and covers part of the semiconductor material layer 140, thereby facilitating control of the heterojunction formed by the second gallium oxide layer 130 and the semiconductor material layer 140. The gate electrode 160 is located between the first electrode 151 and the second electrode 152, as shown in the figure. The gate electrode 160 and the first electrode 151 on the left form a switching device, and the gate electrode 160 and the second electrode 152 on the right form another switching device, with the two switching devices sharing a common source electrode. The material of the gate electrode 160 can be a Ti / Au stack or a Ni / Au stack. Figure 2

[0050] The semiconductor material layer 140 and the second gallium oxide layer 130 located thereunder can form a lateral super-junction, which can withstand a higher voltage and is also referred to as a hetero-super-junction voltage-resistant region. The second gallium oxide layer 130 and the semiconductor material layer 140 located between the first electrode 151 and the gate electrode 160 are used to form a first hetero-super-junction voltage-resistant region, as shown in the figure. The first hetero-super-junction voltage-resistant region is the region where the semiconductor material layer 140 on the left is located, thereby achieving high voltage resistance of the switching device on the left. Figure 2 Figure 2 The second gallium oxide layer 130 and the semiconductor material layer 140 located between the second electrode 152 and the gate electrode 160 are used to form a second hetero-super-junction voltage-resistant region, as shown in the figure. The second hetero-super-junction voltage-resistant region is the region where the semiconductor material layer 140 on the right is located, thereby achieving high voltage resistance of the switching device on the right.

[0051] Compared with the related art, in which one switching device needs to be controlled by one gate electrode 160 and a bidirectional switching device needs to be controlled by two gate electrodes 160, if two gate electrodes 160 are integrated in the bidirectional switching device, the device will have a large lateral voltage-resistant length, the bidirectional switching device will have a large area, and the device cannot be miniaturized. For a medium-low voltage application scenario, for example, 10V-100V, the process preparation of the bidirectional switching device with two gate electrodes 160 is relatively complex, and two separate gate electrode 160 signal driving controls are needed, which leads to complex system control.

[0052] The present application uses a single gate electrode 160 to control two switching devices, that is, both switching devices are controlled by the same gate electrode 160. In a medium-low voltage application scenario, for example, 10V-100V, the gate electrode 160 control can be made simpler, and the bidirectional switching device can be turned on by controlling only the voltage of the single gate electrode 160. There is no need to provide two gate electrodes 160 for the two switching devices, and there is no need for two separate gate electrode 160 signal driving controls, which reduces the complexity of device control and makes the device easier to apply, greatly simplifying the control logic of the bidirectional switching device. In addition, since only one gate electrode 160 needs to be provided, the bidirectional switching device can be further miniaturized.​​

[0053] Next, the working principle of the single-gate bidirectional switch device is described. Bidirectional conduction and bidirectional blocking can be realized. For example, the semiconductor material layer 140 is P-type doped, and the second gallium oxide layer 130 is N-type doped.

[0054] (1) When the gate 160 is grounded, the semiconductor material layer 140 and the contact layer 170 located below the gate 160 are in a weakly depleted state with respect to the second gallium oxide layer 130 (i.e., the channel layer). As shown in FIG. 2, the first electrode 151 and the second electrode 152 are equivalent to having a very large resistance, which hinders the flow of current between the first electrode 151 and the second electrode 152. Figure 3

[0055] (2) Bidirectional conduction: when a positive voltage is applied to the gate 160, a positive bias is formed on the second gallium oxide layer 130 below the ground via hole 190TGV, and electrons are injected in the channel region below the gate 160. As shown in FIG. 3, a current path is formed between the first electrode 151 and the second electrode 152. When the voltage of the first electrode 151 is higher than that of the second electrode 152, the current flows from left to right. When the voltage of the second electrode 152 is higher than that of the first electrode 151, the current flows from right to left, thereby realizing the bidirectional conduction mechanism of the device. Figure 4

[0056] (3) Bidirectional blocking: when a negative voltage is applied to the gate 160, more holes are attracted below the gate 160. As shown in FIG. 4, the left current via hole 190 is completely depleted and turned off, and the right current channel is also completely depleted and turned off. The device is in a bidirectional blocking state and can withstand bidirectional high voltage. Figure 5

[0057] In one possible implementation, the semiconductor material layer 140 between the first electrode 151 and the gate 160 has a first width, and the semiconductor material layer 140 between the second electrode 152 and the gate 160 has a second width. The first width is equal to the second width, or the width difference between the first width and the second width is greater than a preset difference.

[0058] The first width is the width of the semiconductor material layer 140 between the first electrode 151 and the gate 160, as shown in FIG. 2. The first width is the width of the left part of the semiconductor material layer 140, or the width of the first heterojunction super-junction voltage-resistant region. The second width is the width of the semiconductor material layer 140 between the second electrode 152 and the gate 160, as shown in FIG. 4. The second width is the width of the right part of the semiconductor material layer 140, or the width of the second heterojunction super-junction voltage-resistant region. Figure 2 Figure 2

[0059] ​​​​​The first width and the second width can be equal, in other words, the gate 160 can be located at the middle position of the semiconductor material layer 140, and the gate 160 is located at the middle position of the first electrode 151 and the second electrode 152, so that the widths of the two hetero super junction voltage resistance regions are equal, the bidirectional conduction resistance of the device is equal, and the current in the left and right two switching devices is equal, thereby expanding the application scenarios of the single-gate bidirectional switching device. It can be understood that the first width and the second width can be equal can be completely equal or substantially equal.

[0060] The first width and the second width can also be unequal. When the width difference between the two widths is greater than a preset difference, it indicates that the difference between the two widths is large, and the bidirectional conduction resistance of the device will be asymmetric, thereby expanding the application scenarios of the device. The preset difference can be freely set based on actual conditions.

[0061] In a possible implementation, the single-gate bidirectional switching device can further include a contact layer 170 located between the gate 160 and the semiconductor material layer 140. The contact layer 170 has the second conductivity type, and the doping concentration in the contact layer 170 is greater than the doping concentration in the semiconductor material layer 140.

[0062] Specifically, the contact layer 170 and the semiconductor material layer 140 have the same conductivity type, for example, both are P-type, and the doping concentration of the doping element in the contact layer 170 is higher than the doping concentration in the semiconductor material layer 140. As an example, when the semiconductor material layer 140 is nickel oxide, the Ni / O ratio in the contact layer 170 is higher than the Ni / O ratio in the semiconductor material layer 140, the contact layer 170 has more nickel vacancies, and the concentration of P-type carriers is higher, so that the contact layer 170 can better form an ohmic contact with the metal material of the gate 160. The thickness of the contact layer 170 ranges from 10 nm to 300 nm. In actual operation, the contact layer 170 can be prepared by a physical vapor deposition method, and the doping concentration is adjusted by adjusting the manufacturing parameters of the physical vapor deposition process.

[0063] In summary, by setting a higher doping concentration in the contact layer 170, the contact layer 170 has a higher carrier concentration, which can better form an ohmic contact with the gate 160. In addition, the gate 160 and the semiconductor material layer 140 can also be subjected to low-temperature annealing to form a Schottky contact, further reducing the leakage of the gate 160 and improving the performance of the single-gate bidirectional switching device.

[0064] In the embodiments of the present application, the single-gate bidirectional switching device can further include a dielectric layer 180. Referring to Figure 2As shown, the medium layer 180 can be located between the semiconductor material layer 140 and the first electrode 151, and between the semiconductor material layer 140 and the second electrode 152, and the medium layer 180 can also cover the surface of the semiconductor material layer 140 which is not covered by the gate 160, so that the medium layer 180 can realize the protection of the underlying film layer, and separate the first electrode 151, the second electrode 152 and the gate 160. The material of the medium layer 180 can be aluminum oxide, silicon nitride or silicon oxide.

[0065] In a possible implementation, the semiconductor material layer 140 can include a first part 141 and a second part 142 which are separated, the gate 160 covers part of the first part 141 and covers part of the second part 142.

[0066] Reference Figure 6 As shown, the semiconductor material layer 140 can include two separated parts, i.e. a first part 141 and a second part 142, Figure 6 The first part 141 is located on the left side, and the second part 142 is located on the right side. Of course, if the single-gate bidirectional switching device also includes a contact layer 170, the contact layer 170 also includes two separated parts, part of the contact layer 170 is on the first part 141, and part of the contact layer 170 is also on the second part 142.

[0067] The gate 160 as a whole can cover part of the first part 141 and cover part of the second part 142. Since the first part 141 and the second part 142 are separated structures, the gate 160 can be considered as a split gate structure at this time, so as to reduce the injection of carriers in the channel layer into the gate 160 when the second gallium oxide layer 130 is used as the channel layer, and the carriers are captured by the gate 160, which is beneficial to improve the dynamic on-state characteristics of the device. More specifically, this structure can make the carriers in the channel only inject into the gate 160 from one side, for example, the carriers inject into the gate 160 through the first part 141 or the second part 142, effectively reducing the injection of carriers.

[0068] In addition, when the gate 160 is a split gate structure, the widths of the two hetero-super junction voltage resistance regions can be equal or not equal. When the widths are not equal, the dynamic on-state characteristics of the device can be further improved.

[0069] Because the heterojunction voltage-withstand region, while enhancing lateral voltage resistance, also increases the capacitance of the gate 160, hindering an increase in the switching frequency of the gate 160, in one possible implementation, the semiconductor material layer 140 may include a separate third portion 143 and a fourth portion 144, with the third portion 143 located between the first electrode 151 and the fourth portion 144, and the gate 160 partially covering the fourth portion 144. The third portion 143, the fourth portion 144, and the second gallium oxide layer 130 located between the first electrode 151 and the gate 160 form a first heterojunction voltage-withstand region, and the second gallium oxide layer 130 and the fourth portion 144 located between the second electrode 152 and the gate 160 form a second heterojunction voltage-withstand region.

[0070] Next, combine Figure 7 To illustrate, the semiconductor material layer 140 may include a separated third portion 143 and a fourth portion 144. The third portion 143 is closer to the first electrode 151, and the fourth portion 144 is closer to the second electrode 152. The gate 160 may be located above the fourth portion 144, covering a portion of the surface of the fourth portion 144. In short, the original single piece of semiconductor material layer 140 is separated into two portions.

[0071] In this case, in the semiconductor material layer 140, the third portion 143 and the third portion 143 located between the first electrode 151 and the gate 160, together with the second gallium oxide layer 130 located therebelow, form a first heterojunction superjunction withstand voltage region. The fourth portion 144 located between the second electrode 152 and the gate 160, and the second gallium oxide layer 130 located therebelow, form a second heterojunction superjunction withstand voltage region.

[0072] For the first heterojunction voltage-resistant region, it is divided into two voltage-resistant regions, one voltage-resistant region is close to the first electrode 151, and the other voltage-resistant region is close to the gate 160. The area of ​​the voltage-resistant region close to the gate 160 is reduced, or in other words, the width of the semiconductor material layer 140 located under the gate 160 is reduced, thereby reducing the capacitance of the gate 160 to a certain extent. While ensuring that the first heterojunction voltage-resistant region has good lateral voltage resistance, the capacitance of the gate 160 can be reduced, which is beneficial to increasing the switching frequency of the gate 160.

[0073] In order to further reduce the capacitance of the gate 160 and increase the switching frequency of the gate 160, in one possible implementation, the semiconductor material layer 140 may further include a fifth portion 145 separated from the fourth portion 144, and the fifth portion 145 is located between the second electrode 152 and the fourth portion 144; the fifth portion 145 located between the second electrode 152 and the gate 160, the second gallium oxide layer 130 and the fourth portion 144 are used to form a second heterojunction superjunction withstand voltage region.

[0074] Reference Figure 8 As shown in FIG. 1, the semiconductor material layer 140 can further include a fifth portion 145 separated from the fourth portion 144, the fifth portion 145 being closer to the second electrode 152, at this time, the second hetero super junction voltage resistance region can further include the fifth portion 145 and the second gallium oxide layer 130 below the fifth portion 145.

[0075] At this time, the width of the fourth portion 144 for setting the gate 160 can be further reduced, and the second hetero super junction voltage resistance region is realized by the newly added independent fifth portion 145, in short, the originally whole semiconductor material layer 140 is separated into three portions, so as to further reduce the capacitance of the gate 160, and further improve the switching frequency of the gate 160.

[0076] In a possible implementation, the semiconductor material layer 140 is a complete film layer between the first electrode 151 and the second electrode 152.

[0077] Specifically, referring to FIG. 1, the semiconductor material layer 140 is a whole film layer, which realizes full-area coverage of the second gallium oxide layer 130, so as to improve the area of the hetero super junction voltage resistance region, improve the voltage resistance performance of the device, and save the lateral voltage resistance length and the device area. Figure 1 Or Figure 2 As shown in FIG. 1, the semiconductor material layer 140 is a whole film layer, which realizes full-area coverage of the second gallium oxide layer 130, so as to improve the area of the hetero super junction voltage resistance region, improve the voltage resistance performance of the device, and save the lateral voltage resistance length and the device area.

[0078] In a possible implementation, the semiconductor material layer 140 can include a lateral strip structure 146 and a longitudinal strip structure 147, the lateral strip structure 146 extending along the line between the first electrode 151 and the second electrode 152, and the longitudinal strip structure 147 extending in the same direction as the gate 160; the longitudinal strip structure 147 and the lateral strip structure 146 are arranged in a cross manner, and the longitudinal strip structure 147 and the lateral strip structure 146 arranged in the cross manner have cross contact points.

[0079] Reference Figure 9 As shown in FIG. 1, the semiconductor material layer 140 is a whole film layer, which realizes full-area coverage of the second gallium oxide layer 130, so as to improve the area of the hetero super junction voltage resistance region, improve the voltage resistance performance of the device, and save the lateral voltage resistance length and the device area. Figure 10 As shown in FIG. 1, the semiconductor material layer 140 is a whole film layer, which realizes full-area coverage of the second gallium oxide layer 130, so as to improve the area of the hetero super junction voltage resistance region, improve the voltage resistance performance of the device, and save the lateral voltage resistance length and the device area.

[0080] In the embodiments of the present application, considering that the existence of holes in the semiconductor material layer 140 will form a part of the weak PN junction formed by the second gallium oxide layer 130 to be reversedly depleted, and will form scattering to the electron migration of the channel region when the single-gate bidirectional switch is turned on, and increase the conduction loss, therefore, the semiconductor material layer 140 can also not completely cover the second gallium oxide layer 130, and the semiconductor material layer 140 includes a lateral strip structure 146 and a longitudinal strip structure 147, referring to FIG. 1, Figure 9 Or Figure 10As shown, the second gallium oxide layer 130 between the first electrode 151 and the gate 160, and between the second electrode 152 and the gate 160, is covered by the longitudinal strip structures 147 and the transverse strip structures 146. The number and area of ​​the transverse strip structures 146 and the longitudinal strip structures 147 can be set according to actual conditions.

[0081] The horizontal strip structure 146 extends along the line connecting the first electrode 151 and the second electrode 152. The extending direction of the vertical strip structure 147 is the same as the extending direction of the gate 160. That is, the extending directions of the horizontal strip structure 146 and the vertical strip structure 147 are different. Furthermore, the extending directions of the horizontal strip structure 146 and the vertical strip structure 147 are perpendicular to each other. Figure 9 shown.

[0082] The longitudinal strip structures 147 and the transverse strip structures 146 are arranged in an intersecting manner. These intersecting longitudinal strip structures 147 and transverse strip structures 146 have intersecting contact points. This means that the transverse strip structures 147 and transverse strip structures 146 are in contact with each other, thereby electrically connecting the transverse strip structures 146 to adjacent longitudinal strip structures 147 and aligning the potentials of adjacent longitudinal strip structures 147. This ensures uniform voltage distribution between the semiconductor material layer 140 and the second gallium oxide layer 130, thereby reducing the electric field strength of the second gallium oxide layer 130. By replacing the entire semiconductor material layer 140 with the longitudinal strip structures 147 connected by the transverse strip structures 146, the electric field strength is more uniform and smooth, and the peak electric field is reduced, thereby improving the withstand voltage. Furthermore, the area of ​​the semiconductor material layer 140 based on the longitudinal strip structures 147 and transverse strip structures 146 is reduced, thereby reducing parasitic capacitance and improving the reliability of the single-gate bidirectional switch device during dynamic switching.

[0083] Based on the longitudinal strip structure 147 and the transverse strip structure 146, the semiconductor material layer 140 forms a mesh structure, which compromises the contradiction between the transverse super junction formed by the semiconductor material layer 140 and the second gallium oxide layer 130 in the shared drain (or source) portion and the channel conduction. At the same time, when the device is turned off and the reverse withstand voltage is maintained, the reverse withstand voltage electric field distribution between the first electrode 151 and the second electrode 152 is more uniform, so that the device has better reverse withstand voltage reliability, avoids local breakdown caused by local high electric field due to the uneven distribution of P-type conductivity caused by the uneven nickel-oxygen ratio distribution in the semiconductor material layer 140 during manufacturing, and reduces the large PN junction parasitic capacitance formed by the large-area semiconductor material layer 140 and the second gallium oxide layer 130 during the device switching process, thereby reducing switching losses.

[0084] Therefore, the single-gate bidirectional switch device provided by the embodiment of the present application is a bidirectional voltage-resistant switch device with a lateral heterojunction super-junction voltage-resistant structure constructed by the semiconductor material layer 140 and the second gallium oxide layer 130. The heterojunction super-junction voltage-resistant region formed by the semiconductor material layer 140 and the second gallium oxide layer 130 sharing the drain or source part can save the lateral voltage-resistant length and the chip area, and meanwhile, a high-voltage-resistant structure with excellent performance is constructed, thereby realizing the gallium oxide single-gate heterojunction high-voltage-resistant bidirectional switch device.

[0085] From Figure 9 It can be found in the top view that there are discrete multiple ground metal vias 190 in the edge region of the device, which ground the substrate 110 and the unintentionally doped gallium oxide layer UID Ga2O3 on the surface of the substrate 110. In addition, for the ground vias 190, some figures show them and some figures do not show them, which are uniformly described here.

[0086] The material of the aforementioned semiconductor material layer 140 can be gallium nitride, which is described in detail as follows. When the semiconductor material layer 140 is a P-type gallium nitride, the P-type is prone to degradation when the gallium nitride works in a high-temperature environment above 300 degrees Celsius, which leads to the performance degradation of the device.

[0087] Based on this, the gallium nitride can be used as the semiconductor material layer 140. The P-type gallium nitride can form a stable P-type gallium nitride doped layer on the gallium oxide channel layer, and can remain stable at a high temperature above 300 degrees Celsius, thereby ensuring that the single-gate bidirectional switch device can normally work in a high-temperature environment.

[0088] The embodiment of the present application further provides a preparation method of a single-gate bidirectional switch device, which is described with reference to Figure 11 The method includes S101-S102.

[0089] S101, forming a semiconductor material layer 140 on a gallium oxide epitaxial layer, the gallium oxide epitaxial layer includes a substrate 110, a first gallium oxide layer 120 and a second gallium oxide layer 130 which are sequentially stacked, and the semiconductor material layer 140 at least exposes the second gallium oxide layer 130 in the edge region on both sides; the second gallium oxide layer 130 has a first conductivity type, and the semiconductor material layer 140 has a second conductivity type.

[0090] Specifically, the gallium oxide epitaxial layer can be obtained first, which can include a substrate 110, a first gallium oxide layer 120 and a second gallium oxide layer 130 which are sequentially stacked, and the second gallium oxide layer 130 is used as a channel layer. A semiconductor material layer 140 can be grown by a physical vapor deposition method, and the thickness of the semiconductor material layer 140 can range from 10 to 200 nm, and further can range from 20 to 60 nm. Reference Figure 12As shown, from bottom to top, the substrate 110, the first gallium oxide layer 120, the second gallium oxide layer 130 and the semiconductor material layer 140 are sequentially stacked.

[0091] If the contact layer 170 is also included in the single-gate bidirectional switching device, it can be prepared by physical vapor deposition method through photoresist masking in the region of the gate 160. For example, by adjusting the process parameters, a contact layer 170 with higher Ni / O ratio and higher conductivity can be prepared. The thickness of the contact layer 170 can range from 10 nm to 300 nm, for example, it can be 200 nm. Figure 13 As shown, the contact layer 170 covers part of the surface of the semiconductor material layer 140, which is used to form a good ohmic contact with the gate 160 later.

[0092] The semiconductor material layer 140 is selectively etched by a photolithography process, and the semiconductor material layer 140 in the edge region is etched away, so that the underlying second gallium oxide layer 130 is exposed, and the semiconductor material layer 140 in the region of the gate 160 is retained. Reference Figure 14 As shown, the semiconductor material layer 140 on both sides is removed, and the semiconductor material layer 140 in the middle region is retained.

[0093] In addition, considering the insulation problem between the first electrode 151, the second electrode 152 and the gate 160 later, a dielectric layer 180 can be formed after the semiconductor material layer 140 is formed, reference Figure 15 As shown, the dielectric layer 180 can cover the exposed semiconductor material layer 140, the second gallium oxide layer 130 and the contact layer 170. The dielectric layer 180 acts as a passivation layer, and the material of the dielectric layer 180 can be at least one of Al2O3, SiO2 and SiN.

[0094] S102, forming the first electrode 151 and the second electrode 152 on the second gallium oxide layer 130 located in the two side edge regions, and forming the gate 160 on the semiconductor material layer 140. The first electrode 151 and the second electrode 152 are both source electrodes or both drain electrodes. The gate 160 covers part of the semiconductor material layer 140, and is located between the first electrode 151 and the second electrode 152. The second gallium oxide layer 130 and the semiconductor material layer 140 between the first electrode 151 and the gate 160 are used to form a first heterojunction super-junction voltage-resistant region. The second gallium oxide layer 130 and the semiconductor material layer 140 between the second electrode 152 and the gate 160 are used to form a second heterojunction super-junction voltage-resistant region.

[0095] When the dielectric layer 180 is included in the single-gate bidirectional switching device, the dielectric layer 180 can be locally and selectively etched to expose part of the surface of the second gallium oxide layer 130 for setting the first electrode 151 and the second electrode 152, and to expose part of the surface of the contact layer 170 for setting the gate 160.

[0096] The first electrode 151 and the second electrode 152 are formed above the second gallium oxide layer 130 located at the two side edge regions, and the gate 160 is formed above the semiconductor material layer 140, covering part of the surface of the semiconductor material layer 140. The electrodes and the gate 160 can be formed by electron beam evaporation, and the materials of the electrodes and the gate 160 can be Ti / Au or Ni / Au.

[0097] Thus, the second gallium oxide layer 130 and the semiconductor material layer 140 located between the first electrode 151 and the gate 160 are used to form a first hetero-super junction voltage-resistant region, thereby achieving high voltage resistance of one switching device, and the second gallium oxide layer 130 and the semiconductor material layer 140 located between the second electrode 152 and the gate 160 are used to form a second hetero-super junction voltage-resistant region, thereby achieving high voltage resistance of another switching device. The present application uses a single gate 160 to control a double switching device, i.e., both switching devices are controlled by the same gate 160. In a medium-low voltage application scenario, for example, 10V-100V, the gate 160 control is simpler, and the double switching device can be turned on by controlling the voltage of the single gate 160, without the need to set two gates 160 for the double switching device and without the need to separately drive and control two gate 160 signals, thereby reducing the complexity of device control and making the device easier to apply, and greatly simplifying the control logic of the bidirectional switching device.

[0098] In addition, when the semiconductor material layer 140 is in a grid structure, the preparation can be achieved by changing the layout design of the mask plate.

[0099] Based on the single-gate bidirectional switching device provided in the above embodiments, the present application further provides a single-gate bidirectional switching device, specifically a single-gate bidirectional switching device based on a high electron mobility transistor (HEMT). The single-gate bidirectional switching device includes a substrate 200, a buffer layer 210, a channel layer 220, a barrier layer 230, a semiconductor material layer 240, a first electrode 251, a second electrode 252, and a gate 260. For the similar parts of the single-gate bidirectional switching device based on the HEMT and the foregoing single-gate bidirectional switching device, no further description is provided, and reference can be made to the foregoing description.

[0100] The substrate 200, the buffer layer 210, the channel layer 220, the barrier layer 230, and the semiconductor material layer 240 are sequentially stacked, and the first electrode 251, the second electrode 252, and the gate 260 are sequentially formed on the semiconductor material layer 240.Figure 16 The semiconductor material layer 240 does not completely cover the barrier layer 230, and the semiconductor material layer 240 exposes the barrier layer 230 at least at the two side edge regions.

[0101] The substrate 110 can be a semi-insulating substrate, a silicon substrate or a sapphire substrate for supporting the gallium nitride bidirectional switch device. The barrier layer 230 and the channel layer 220 are of a first conductivity type, and the semiconductor material layer 240 is of a second conductivity type. The material of the barrier layer 230 is aluminum gallium nitride, and the materials of the channel layer 220 and the buffer layer 210 are gallium nitride. The thickness of the buffer layer 210 ranges from 200 nm to 6000 nm, the thickness of the channel layer 220 ranges from 20 nm to 200 nm, the thickness of the barrier layer 230 ranges from 5 nm to 50 nm, and the thickness of the semiconductor material layer 240 ranges from 10 nm to 60 nm.

[0102] The gate 260 is disposed on the side of the semiconductor material layer 240 away from the substrate 200, and the first electrode 251 and the second electrode 252 are disposed on one side of the barrier layer 230. The first electrode 251 can be one of a source electrode or a drain electrode, and the electrode type of the first electrode 251 and the electrode type of the second electrode 252 are the same, that is, when the first electrode 251 is a source electrode, the second electrode 252 is also a source electrode, and the single-gate bidirectional switch device is a common-drain device. The gate 260 is located between the first electrode 251 and the second electrode 252.

[0103] The high electron mobility transistor (HEMT) is also called a modulation-doped FET (MODFET), which is a field effect transistor that uses two materials with different energy gaps to form a heterojunction to provide a channel for carriers. The channel 220 and the barrier layer 230 can form a polar two-dimensional electron gas channel 2DEG, which has a lower on-resistance and can optimize the switching characteristics of the device, thereby reducing the on-resistance of the device while achieving high voltage resistance through the hetero super junction voltage resistance region. The semiconductor material layer 240 can be gallium nitride, gallium oxide or iridium gallium oxide, etc.

[0104] In one possible implementation, the channel layer is a GaO channel layer, and the barrier layer is an AlGaO barrier layer; or, the channel layer is a GAN channel layer, and the barrier layer is an AlGaN barrier layer. In short, the GaO channel layer and the AlGaO barrier layer can form a polar two-dimensional electron gas channel, and the GAN channel layer and the AlGaN barrier layer can also form a polar two-dimensional electron gas channel.

[0105] In addition, the semiconductor material layer 240 can include lateral strip structures 241 extending along the line between the first electrode 251 and the second electrode 252, and longitudinal strip structures 242 extending in the same direction as the gate 260. The longitudinal strip structures 242 and the lateral strip structures 241 are arranged in a cross manner, and the cross arranged longitudinal strip structures 242 and the lateral strip structures 241 have cross contact points. For details, refer to the foregoing description, which will not be repeated here.

[0106] In the embodiments of the present application, a contact layer 270 is further included, and the material of the contact layer 270 can be consistent with the material of the semiconductor material layer 240, for example, both can be nickel oxide or both can be gallium nitride. The contact layer 270 is of the second conductivity type, and the doping concentration of the contact layer 270 is greater than the doping concentration of the semiconductor material layer 240. The contact layer 270 is used to realize good ohmic contact with the gate 260.

[0107] In the embodiments of the present application, a dielectric layer 280 can be further included, and the dielectric layer 280 is arranged between the semiconductor material layer 240 and the first electrode 251, arranged between the semiconductor material layer 240 and the second electrode 252, and arranged above the semiconductor material layer 240. That is, the dielectric layer 280 is used to separate the semiconductor material layer 240 and the first electrode 251 and the second electrode 252. For details, refer to the foregoing description, which will not be repeated here.

[0108] Each of the embodiments in the present specification is described in a progressive manner, and the same or similar parts of each of the embodiments can be referred to each other. Each of the embodiments focuses on the difference from other embodiments. In particular, for the method embodiments, since they are basically similar to the device embodiments, the description is relatively simple, and the relevant parts can refer to the part of the description of the device embodiments.

[0109] The above description is only the preferred embodiments of the present application. Although the present application has been disclosed as above with the preferred embodiments, it is not intended to limit the present application. Any person skilled in the art can make many possible changes and modifications to the technical solutions of the present application, or modify equivalent embodiments with the above disclosed methods and technical contents without departing from the scope of the technical solutions of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the technical solutions of the present application, are still within the scope of protection of the technical solutions of the present application.

Claims

1. A single-gate bidirectional switch device, characterized in that: include: A substrate, a first gallium oxide layer, a second gallium oxide layer, and a semiconductor material layer sequentially stacked along a stacking direction; The semiconductor material layer covers a portion of the second gallium oxide layer, the second gallium oxide layer has a first conductivity type, and the semiconductor material layer has a second conductivity type; a first electrode and a second electrode located on a side of the second gallium oxide layer away from the first gallium oxide layer, wherein the first electrode and the second electrode are both source electrodes or both drain electrodes; a gate located on a side of the semiconductor material layer away from the second gallium oxide layer; The gate covers a portion of the semiconductor material layer, and the gate is located between the first electrode and the second electrode; The second gallium oxide layer and the semiconductor material layer located between the first electrode and the gate are used to form a first heterojunction superjunction withstand voltage region, and the second gallium oxide layer and the semiconductor material layer located between the second electrode and the gate are used to form a second heterojunction superjunction withstand voltage region.

2. The single-gate bidirectional switch device according to claim 1, characterized in that: The semiconductor material layer located between the first electrode and the gate has a first width, and the semiconductor material layer located between the second electrode and the gate has a second width; The first width is equal to the second width, or a width difference between the first width and the second width is greater than a preset difference.

3. The single-gate bidirectional switch device according to claim 1, wherein: The semiconductor material layer includes a first portion and a second portion separated from each other, and the gate covers a portion of the first portion and a portion of the second portion.

4. The single-gate bidirectional switch device according to claim 1, wherein: The semiconductor material layer includes a third portion and a fourth portion separated from each other, the third portion is located between the first electrode and the fourth portion, and the gate covers a portion of the fourth portion; The third portion, the fourth portion, and the second gallium oxide layer located between the first electrode and the gate are used to form the first heterojunction superjunction voltage-withstand region, and the second gallium oxide layer and the fourth portion located between the second electrode and the gate are used to form the second heterojunction superjunction voltage-withstand region.

5. The single-gate bidirectional switch device according to claim 4, characterized in that: The semiconductor material layer further includes a fifth portion separated from the fourth portion, and the fifth portion is located between the second electrode and the fourth portion; The fifth portion, the second gallium oxide layer, and the fourth portion located between the second electrode and the gate are used to form the second heterojunction voltage-withstanding region.

6. The single-gate bidirectional switch device according to any one of claims 1 to 5, characterized in that: The semiconductor material layer is a complete film layer located between the first electrode and the second electrode.

7. The single-gate bidirectional switch device according to any one of claims 1 to 5, characterized in that: The semiconductor material layer includes a transverse strip structure and a longitudinal strip structure, wherein the transverse strip structure extends along a line connecting the first electrode and the second electrode, and the longitudinal strip structure extends in the same direction as the gate; The longitudinal strip structures and the transverse strip structures are arranged crosswise, and the crosswise longitudinal strip structures and the transverse strip structures have cross contact points.

8. The single-gate bidirectional switch device according to any one of claims 1 to 5, characterized in that: The method further includes a contact layer located between the gate and the semiconductor material layer, wherein the contact layer has the second conductivity type and a doping concentration in the contact layer is greater than a doping concentration in the semiconductor material layer.

9. The single-gate bidirectional switch device according to any one of claims 1 to 5, characterized in that: The semiconductor material layer is made of nickel oxide, gallium nitride or iridium gallium oxide.

10. A method for preparing a single-gate bidirectional switch device, characterized in that: The method comprises: forming a semiconductor material layer on the gallium oxide epitaxial layer, the gallium oxide epitaxial layer comprising a substrate, a first gallium oxide layer, and a second gallium oxide layer stacked in sequence, the semiconductor material layer exposing at least the second gallium oxide layer located at two side edge regions; the second gallium oxide layer having a first conductivity type, and the semiconductor material layer having a second conductivity type; A first electrode and a second electrode are formed on the second gallium oxide layer located in the edge areas on both sides, and a gate is formed on the semiconductor material layer. The first electrode and the second electrode are both source electrodes or both drain electrodes. The gate covers part of the semiconductor material layer. The gate is located between the first electrode and the second electrode. The second gallium oxide layer and the semiconductor material layer located between the first electrode and the gate are used to form a first heterojunction superjunction withstand voltage region. The second gallium oxide layer and the semiconductor material layer located between the second electrode and the gate are used to form a second heterojunction superjunction withstand voltage region.

11. A single-gate bidirectional switch device, characterized in that: The single-gate bidirectional switch device comprises: a substrate, a buffer layer, a channel layer, a barrier layer, a semiconductor material layer, a first electrode, a second electrode and a gate; The substrate, the buffer layer, the channel layer, the barrier layer, and the semiconductor material layer are stacked in sequence, the gate is arranged on a side of the semiconductor material layer away from the substrate, the first electrode and the second electrode are arranged on one side of the barrier layer, and the gate is located between the first electrode and the second electrode; The barrier layer and the channel layer are of a first conductivity type, and the semiconductor material layer is of a second conductivity type.

12. The single-gate bidirectional switch device according to claim 11, characterized in that: The channel layer is a GaO channel layer, and the barrier layer is an AlGaO barrier layer; Alternatively, the channel layer is a GaN channel layer, and the barrier layer is an AlGaN barrier layer.

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