A photoelectrically controlled hybrid tunnel junction bipolar transistor and its preparation method

Abstract

The present invention discloses a photoelectrically co-regulated hybrid tunnel junction bipolar transistor, relating to the field of semiconductors. The bipolar transistor comprises: a substrate, a third N-type gallium nitride layer disposed on the substrate, a second P-type gallium nitride layer and an emitter metal contact layer disposed on the substrate, a base metal contact layer and a first P-type heavily doped gallium nitride layer disposed on the second P-type gallium nitride layer, an unintentionally doped gallium nitride indium polarization layer disposed sequentially on the first P-type heavily doped gallium nitride layer, a second N-type heavily doped gallium nitride layer, a first N-type gallium nitride layer, and a collector metal contact layer disposed on the first N-type gallium nitride layer. By providing a tunnel junction, the present invention can enhance hole injection, reduce device resistance, and improve device response speed. The present invention overcomes the process difficulties of metal organic chemical vapor deposition (MOCVD) fabrication by introducing hydrogen deficiency during molecular beam epitaxial growth, thereby reducing the process difficulty of manufacturing tunnel junction devices and improving device performance.

Description

Technical Field

[0001] The present invention relates to the field of optoelectronic display, and in particular to a photoelectric co-regulated hybrid tunnel junction bipolar transistor and a preparation method thereof. Background Art

[0002] Gallium nitride (GaN) materials have attracted considerable attention due to their unique physical properties and are widely used in the fabrication of high-performance optoelectronic devices. Their advantages, including a wide bandgap, high electron mobility, and excellent physical and chemical stability, make them crucial in the optoelectronics field. Recently, the monolithic integration of GaN-based electronic drivers and GaN-based blue LEDs, such as MOSFETs and HEMTs, has significantly improved the reliability and performance of these integrated devices, as GaN-based light-emitting and light-detecting devices cover the entire wavelength range from ultraviolet to visible light. The ability to integrate a transmitter and receiver on a single chip offers new possibilities for the design of wireless communication modules.

[0003] Tunnel junctions (TJs) are considered an effective means of improving current spreading and injection in nitride-based optoelectronic devices. TJ structures typically require highly doped p / n-GaN as the pn junction interface. Under a specific reverse bias, electrons can tunnel from the valence band of p-GaN to the conduction band of n-GaN, ultimately leading to the efficient injection of holes into the active region. TJ-BJTs can act as both receivers and transmitters, adjusting output current and light intensity by varying the optical input power or base voltage. Combining TJ tunnel junctions with conventional control devices (BJTs) can enable BJT devices to achieve lower turn-on voltages and higher switching speeds, thereby reducing power consumption and improving device efficiency. This improves the switching speed and frequency response of the device, making it more suitable for high-frequency applications. However, since GaN is a wide bandgap semiconductor with a bandgap width of 3.4eV at room temperature, the probability of direct band-to-band tunneling is low, so achieving n / p homojunction tunneling remains challenging. In addition, due to the relatively difficult hydrogen passivation and hydrogen atom diffusion, the buried p-GaN layer under the highly doped n-GaN is not easily activated. Therefore, highly doped p-type GaN is difficult to prepare by metal organic chemical vapor deposition (MOCVD). Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the technical problem to be solved by the present invention is to provide a hybrid tunnel junction bipolar transistor with photoelectric co-regulation. The purpose is to grow the tunnel junction through molecular beam epitaxy (MBE), thereby enhancing hole injection, reducing device resistance, and improving device response speed; increasing ultraviolet light sensitivity; improving the photoelectric conversion efficiency of ultraviolet light in the collector region; increasing current gain and output current density; and reducing power consumption. Furthermore, the present invention overcomes the process difficulties of tunnel junction fabrication using metal-organic chemical vapor deposition (MOCVD) by introducing hydrogen deficiency during the MBE growth process, thereby reducing the manufacturing process difficulty of the tunnel junction device and improving device performance.

[0005] To achieve the above objectives, in a first aspect of the present invention, a photoelectrically co-regulated hybrid tunnel junction bipolar transistor is provided, the bipolar transistor comprising:

[0006] substrate;

[0007] a third N-type gallium nitride layer disposed on the substrate;

[0008] A second P-type gallium nitride layer and an emitter metal contact layer 9 are provided on the substrate;

[0009] a base metal contact layer and a first P-type heavily doped gallium nitride layer disposed on the second P-type gallium nitride layer;

[0010] an unintentionally doped gallium nitride indium polarization layer, a second N-type heavily doped gallium nitride layer, and a first N-type gallium nitride layer sequentially disposed on the first P-type heavily doped gallium nitride layer;

[0011] and a collector metal contact layer disposed on the first N-type gallium nitride layer;

[0012] The first P-type heavily doped gallium nitride layer, the unintentionally doped gallium nitride indium polarization layer, the second N-type heavily doped gallium nitride layer 2, and the first N-type gallium nitride layer are grown in sequence by molecular beam epitaxy (MBE).

[0013] In a specific embodiment, a buffer layer is further provided between the substrate and the third N-type gallium nitride layer.

[0014] In a specific embodiment, the materials of the base metal contact layer and the collector metal contact layer are translucent nickel / gold metal stacks; the materials of the emitter metal contact layer include molybdenum, tungsten, titanium, nickel, gold, silver, cadmium and platinum.

[0015] In a specific embodiment, the second N-type heavily doped gallium nitride layer and the first P-type heavily doped gallium nitride layer are highly doped, with a doping concentration of 1×1018 / to 1×1021 / .

[0016] In a specific embodiment, the second N-type heavily doped gallium nitride layer and the first P-type heavily doped gallium nitride layer are ultra-thin gallium nitride layers, wherein the thickness of the second N-type heavily doped gallium nitride layer is 20nm-40nm, and the thickness of the first P-type heavily doped gallium nitride layer is 10nm-20nm, thereby forming a TJ tunnel junction structure.

[0017] In a specific embodiment, the unintentionally doped gallium indium nitride polarization layer 3 has a thickness of an ultra-thin layer of 1 nm to 2 nm.

[0018] In a second aspect of the present invention, a method for preparing a photoelectrically co-regulated hybrid tunnel junction bipolar transistor is provided, comprising the following steps:

[0019] S1: depositing a third N-type gallium nitride layer on the substrate by using a vapor deposition method, and depositing a second P-type gallium nitride layer on the third N-type gallium nitride layer by using a vapor deposition method;

[0020] S2: using molecular beam epitaxy (MBE) to sequentially grow a first P-type heavily doped gallium nitride layer, an unintentionally doped gallium nitride indium polarization layer, a second N-type heavily doped gallium nitride layer, and a first N-type gallium nitride layer on the second P-type gallium nitride layer;

[0021] S3: Based on the mask, retain the collector region, and sequentially etch and remove a portion of the first N-type gallium nitride layer, the second N-type heavily doped gallium nitride layer, the unintentionally doped gallium nitride indium polarization layer, and the first P-type heavily doped gallium nitride layer in the base region; and sequentially etch and remove a portion of the first N-type gallium nitride layer, the second N-type heavily doped gallium nitride layer, the unintentionally doped gallium nitride indium polarization layer, the first P-type heavily doped gallium nitride layer, and the second P-type gallium nitride layer in the emitter region;

[0022] S4: generating a collector metal contact layer in the collector region, generating a base metal contact layer in the base region, and generating an emitter metal contact layer in the emitter region.

[0023] In a specific embodiment, the second N-type heavily doped gallium nitride layer and the first P-type heavily doped gallium nitride layer are highly doped, with a doping concentration of 1×1018 / to 1×1021 / .

[0024] In a specific embodiment, the second N-type heavily doped gallium nitride layer and the first P-type heavily doped gallium nitride layer are ultra-thin gallium nitride layers, wherein the thickness of the second N-type heavily doped gallium nitride layer is 20nm-40nm, and the thickness of the first P-type heavily doped gallium nitride layer is 10nm-20nm, thereby forming a TJ tunnel junction structure.

[0025] In a specific embodiment, the unintentionally doped gallium indium nitride polarization layer 3 has a thickness of an ultra-thin layer of 1 nm to 2 nm.

[0026] Beneficial effects of the present invention: 1) The present invention adds a TJ tunnel junction structure to the original BJT device, so that the TJ-BJT device can be used as both a receiver and a transmitter, and can be adjusted by changing the optical input power or the base voltage. Moreover, the device can be driven solely by the base voltage and ultraviolet light, and is a multifunctional integrated device that integrates light emission, detection, sensing, driving, and regulation. 2) The preparation method provided by the present invention realizes the integration of gallium nitride-based BJT devices and gallium nitride-based TJ tunnel junctions, and can achieve the control of the collector current with a lower base current, and achieve the control function of the device with a lower power ultraviolet light, thereby improving the current gain of the device. 3) The present invention adopts the MBE method to grow a high-doping concentration TJ tunnel junction structure. Compared with the MOCVD method, this method is easier to activate the highly doped P-type GaN under the highly doped N-type GaN, thereby realizing the tunneling effect of the electron homojunction, and solving the difficulty of not being able to manufacture a high-doping concentration P-type GaN layer using traditional methods. 4) By designing a tunnel junction, the present invention enhances hole injection, reduces device resistance, improves device response speed, enhances UV light sensitivity, improves UV light photoelectric conversion efficiency in the collector region, increases current gain and output current density, and reduces power consumption. 5) The present invention overcomes the process difficulties of tunnel junction fabrication using metal-organic chemical vapor deposition (MOCVD) by introducing hydrogen deficiency during molecular beam epitaxy (MBE) growth, reducing the manufacturing complexity of tunnel junction devices and improving device performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic structural diagram of a photoelectrically co-regulated hybrid tunnel junction bipolar transistor in one embodiment of the present invention;

[0028] Figure 2-a 、 Figure 2-b 、 Figure 2-c 、 Figure 2-d It is a process flow diagram of a method for preparing a photoelectrically co-regulated hybrid tunnel junction bipolar transistor in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0029] The following describes in detail embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0030] In the description of this patent, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing this patent and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on this patent.

[0031] In the description of this patent, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," "connected," and "set" should be understood in a broad sense. For example, they can refer to fixed connection or set, detachable connection or set, or integral connection or set. Those skilled in the art will understand the specific meanings of the above terms in this patent based on the specific circumstances.

[0032] The embodiment of the present invention provides a hybrid tunnel junction bipolar transistor with photoelectric co-regulation, such as Figure 1 、 Figure 2-a 、 Figure 2-b 、 Figure 2-c 、 Figure 2-d As shown, the bipolar transistor includes:

[0033] substrate 8;

[0034] a third N-type gallium nitride layer 6 disposed on the substrate 8;

[0035] A second P-type gallium nitride layer 5 and an emitter metal contact layer 9 are provided on the substrate 8;

[0036] A base metal contact layer 10 and a first P-type heavily doped gallium nitride layer 4 are provided on the second P-type gallium nitride layer 5;

[0037] An unintentionally doped indium gallium nitride polarization layer 3, a second N-type heavily doped gallium nitride layer 2, and a first N-type gallium nitride layer 1 are sequentially provided on the first P-type heavily doped gallium nitride layer 4;

[0038] and a collector metal contact layer 11 disposed on the first N-type gallium nitride layer 1;

[0039] The first P-type heavily doped gallium nitride layer 4, the unintentionally doped gallium indium nitride polarization layer 3, the second N-type heavily doped gallium nitride layer 2, and the first N-type gallium nitride layer 1 are grown in sequence by molecular beam epitaxy (MBE).

[0040] It is worth mentioning that in Figure 1The emitter region corresponding to the emitter metal contact layer 9 is located on the right side. In fact, the emitter region can also be located on the left side of the base region. Its function is essentially the same as Figure 1 same.

[0041] In this embodiment, a buffer layer 7 is further provided between the substrate 8 and the third N-type gallium nitride layer 6 .

[0042] Typically, the buffer layer 7 may be made of undoped gallium nitride, or other nitrides or silicides.

[0043] It is worth mentioning that the base metal contact layer 10 and the collector metal contact layer 11 are made of a translucent nickel / gold metal stack. Typically, the translucent material can be a translucent material itself, or can be made translucent through a hollow or window design.

[0044] It is worth mentioning that the material of the emitter metal contact layer 9 includes but is not limited to molybdenum, tungsten, titanium, nickel, gold, silver, cadmium and platinum.

[0045] Optionally, the second N-type heavily doped gallium nitride layer 2 and the first P-type heavily doped gallium nitride layer 4 are highly doped, with a doping concentration of 1×10 18 / to 1×10 21 / Preferably, in this embodiment, the doping concentration is 1×10 20 / It is worth mentioning that in actual process applications, the actual doping concentration may deviate slightly due to factors such as the process, and the actual application effect is similar and also falls within the scope of protection of this application.

[0046] Optionally, the second N-type heavily doped gallium nitride layer 2 and the first P-type heavily doped gallium nitride layer 4 are ultra-thin gallium nitride layers, wherein the thickness of the second N-type heavily doped gallium nitride layer 2 is 20nm-40nm, and the thickness of the first P-type heavily doped gallium nitride layer 4 is 10nm-20nm, thereby forming a TJ tunnel junction structure.

[0047] Preferably and exemplarily, in this embodiment, the thickness of the second N-type heavily doped gallium nitride layer 2 is 30 nm, and the thickness of the first P-type heavily doped gallium nitride layer 4 is 15 nm.

[0048] Optionally, the unintentionally doped gallium indium nitride polarization layer 3 has a thickness of an ultra-thin layer of 1 nm to 2 nm.

[0049] Typically, in this embodiment, the thickness of the unintentionally doped gallium indium nitride polarization layer 3 is 1.5 nm.

[0050] Typically, the etching method in step S4 may be ICP dry etching, exposure-development wet etching, etc. In ICP dry etching, a glass-based mask may be used to mask the relevant area.

[0051] like Figure 1 、 Figure 2-a 、 Figure 2-b 、 Figure 2-c 、 Figure 2-d As shown, the present invention is further described below with respect to the process preparation method. A second embodiment of the present invention provides a method for preparing a photoelectrically co-regulated hybrid tunnel junction bipolar transistor, and an exemplary description is given. The method includes the following steps:

[0052] S1: depositing a third N-type gallium nitride layer 6 on a substrate 8 by vapor deposition, and depositing a second P-type gallium nitride layer 5 on the third N-type gallium nitride layer 6 by vapor deposition;

[0053] It is worth mentioning that the wafer obtained after step S1 can be annealed. At the same time, the wafer obtained in step S1 can also be treated with hydrofluoric acid to remove residual O and Mg on the surface of the epitaxial wafer.

[0054] In addition, a buffer layer 7 may be provided between the substrate 8 and the third N-type gallium nitride layer 6. Typically, the buffer layer 7 may be made of undoped gallium nitride, or other nitrides or silicides.

[0055] S2: using molecular beam epitaxy (MBE) to sequentially grow a first P-type heavily doped gallium nitride layer 4, an unintentionally doped gallium indium nitride polarization layer 3, a second N-type heavily doped gallium nitride layer 2, and a first N-type gallium nitride layer 1 on the second P-type gallium nitride layer 5; the result of step S2 is as follows: Figure 2-a shown.

[0056] S3: Based on the mask, retain the collector area, such as Figure 2-b As shown, the first N-type gallium nitride layer 1, the second N-type heavily doped gallium nitride layer 2, the unintentionally doped gallium nitride indium polarization layer 3, and the first P-type heavily doped gallium nitride layer 4 are sequentially etched and removed in the base region. Figure 2-c As shown, in the emitter region, a portion of the first N-type gallium nitride layer 1, the second N-type heavily doped gallium nitride layer 2, the unintentionally doped gallium indium nitride polarization layer 3, the first P-type heavily doped gallium nitride layer 4, and the second P-type gallium nitride layer 5 are sequentially etched and removed;

[0057] S4: As Figure 2-d As shown, a collector metal contact layer 11 is generated in the collector region, a base metal contact layer 10 is generated in the base region, and an emitter metal contact layer 9 is generated in the emitter region.

[0058] It is worth mentioning that the material of the base metal contact layer 10 and the collector metal contact layer 11 can be a translucent nickel / gold metal stack; typically, the translucent material can be a translucent material itself, or it can be translucent through hollowing or window design.

[0059] It is worth mentioning that the material of the emitter metal contact layer 9 includes but is not limited to molybdenum, tungsten, titanium, nickel, gold, silver, cadmium and platinum.

[0060] Typically, step S4 can use electron beam evaporation, sputtering technology, screen printing and other technologies to produce the metal contact layer; at the same time, from the perspective of additive and subtractive thin film generation, the entire layer can be coated and then etched, or a local mask can be used for direct coating.

[0061] Furthermore, optionally, the second N-type heavily doped gallium nitride layer 2 and the first P-type heavily doped gallium nitride layer 4 are highly doped, with a doping concentration of 1×10 18 / to 1×10 21 / .

[0062] Preferably, in this embodiment, the doping concentration is 1×10 20 / .

[0063] Optionally, the second N-type heavily doped gallium nitride layer 2 and the first P-type heavily doped gallium nitride layer 4 are ultra-thin gallium nitride layers, wherein the thickness of the second N-type heavily doped gallium nitride layer 2 is 20nm-40nm, and the thickness of the first P-type heavily doped gallium nitride layer 4 is 10nm-20nm, thereby forming a TJ tunnel junction structure.

[0064] Preferably, in this embodiment, the thickness of the second N-type heavily doped gallium nitride layer 2 is 30 nm, and the thickness of the first P-type heavily doped gallium nitride layer 4 is 15 nm.

[0065] Optionally, the unintentionally doped gallium indium nitride polarization layer 3 has a thickness of an ultra-thin layer of 1 nm to 2 nm.

[0066] Preferably, in this embodiment, the thickness of the unintentionally doped gallium indium nitride polarization layer 3 is 1.5 nm.

[0067] Typically, the etching method in step S4 may be ICP dry etching, exposure-development wet etching, etc. In ICP dry etching, a glass-based mask may be used to mask the relevant area.

[0068] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A hybrid tunnel junction bipolar transistor with photoelectric co-regulation, characterized in that: The bipolar transistor comprises: substrate; a third N-type gallium nitride layer disposed on the substrate; a second P-type gallium nitride layer and an emitter metal contact layer disposed on the substrate; a base metal contact layer and a first P-type heavily doped gallium nitride layer disposed on the second P-type gallium nitride layer; an unintentionally doped gallium nitride indium polarization layer, a second N-type heavily doped gallium nitride layer, and a first N-type gallium nitride layer sequentially disposed on the first P-type heavily doped gallium nitride layer; and a collector metal contact layer disposed on the first N-type gallium nitride layer; The first P-type heavily doped gallium nitride layer, the unintentionally doped gallium nitride indium polarization layer, the second N-type heavily doped gallium nitride layer, and the first N-type gallium nitride layer are grown in sequence by molecular beam epitaxy (MBE). The second N-type heavily doped gallium nitride layer and the first P-type heavily doped gallium nitride layer are ultra-thin gallium nitride layers, wherein the thickness of the second N-type heavily doped gallium nitride layer is 20 nm-40 nm, and the thickness of the first P-type heavily doped gallium nitride layer is 10 nm-20 nm, thereby forming a TJ tunnel junction structure; The thickness of the unintentionally doped gallium indium nitride polarization layer is an ultra-thin layer of 1nm-2nm; The preparation method of the bipolar transistor comprises the following steps: S1: depositing a third N-type gallium nitride layer on the substrate by using a vapor deposition method, and depositing a second P-type gallium nitride layer on the third N-type gallium nitride layer by using a vapor deposition method; S2: using molecular beam epitaxy (MBE) to sequentially grow a first P-type heavily doped gallium nitride layer, an unintentionally doped gallium nitride indium polarization layer, a second N-type heavily doped gallium nitride layer, and a first N-type gallium nitride layer on the second P-type gallium nitride layer; S3: Based on the mask, retain the collector region, and sequentially etch and remove a portion of the first N-type gallium nitride layer, the second N-type heavily doped gallium nitride layer, the unintentionally doped gallium nitride indium polarization layer, and the first P-type heavily doped gallium nitride layer in the base region; and sequentially etch and remove a portion of the first N-type gallium nitride layer, the second N-type heavily doped gallium nitride layer, the unintentionally doped gallium nitride indium polarization layer, the first P-type heavily doped gallium nitride layer, and the second P-type gallium nitride layer in the emitter region; S4: generating a collector metal contact layer in the collector region, generating a base metal contact layer in the base region, and generating an emitter metal contact layer in the emitter region.

2. The photoelectrically controlled hybrid tunnel junction bipolar transistor according to claim 1, characterized in that: A buffer layer is further provided between the substrate and the third N-type gallium nitride layer.

3. The photoelectrically controlled hybrid tunnel junction bipolar transistor according to claim 1, wherein: The materials of the base metal contact layer and the collector metal contact layer are semi-transparent nickel / gold metal stacks; the materials of the emitter metal contact layer include molybdenum, tungsten, titanium, nickel, gold, silver, cadmium and platinum.

4. The photoelectrically controlled hybrid tunnel junction bipolar transistor according to claim 1, wherein: The second N-type heavily doped gallium nitride layer and the first P-type heavily doped gallium nitride layer are highly doped, with a doping concentration of 1×1018 / to 1×1021 / .

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