A schottky contact super barrier rectifier

Abstract

The application provides a Schottky contact super-barrier rectifier, which forms a low electron barrier structure based on an anode metal layer, a first conductive type polysilicon layer, an oxide layer and a second conductive type low electron barrier germanium silicon region, and the low electron barrier structure is an anode structure of the rectifier; when the rectifier is forward conducted, electrons will flow more easily from a cathode to an anode, and a smaller conduction voltage is achieved. Therefore, the rectifier can increase the thickness of the oxide layer without deteriorating the forward conduction voltage and the reverse leakage current; the single particle gate penetration characteristic of the Schottky contact super-barrier rectifier is improved by increasing the thickness of the oxide layer without degrading the basic electrical characteristics, so as to improve the anti-single particle gate penetration performance.

Description

Technical Field

[0001] This invention relates to the field of power semiconductor power electronic device technology, and specifically to a Schottky contact superbarrier rectifier. Background Technology

[0002] With the development of power integrated circuits, the development of power semiconductor devices is booming. Power semiconductor rectifiers are an important type of semiconductor device, playing a crucial role in power supplies and power converters.

[0003] The Schottky Contact Super Barrier Rectifier (SSBR) emerged in this context, representing a new type of power semiconductor rectifier with excellent performance and a simple manufacturing process. It exhibits good performance in terms of low forward voltage, small reverse leakage current, and short reverse recovery time, making it a superior choice for power semiconductor rectifiers.

[0004] However, due to the thin gate oxide layer, super barrier rectifiers are prone to single-event gate-through (SET) damage when operating in cosmic heavy-ion radiation environments, leading to permanent device failure. This results in insufficient reliability due to SET performance.

[0005] Therefore, improving the single-gate breakdown resistance of Schottky contact superbarrier rectifiers is an urgent problem to be solved. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the present invention provides a Schottky contact superbarrier rectifier to solve at least one of the above-mentioned technical problems.

[0007] To achieve the above-mentioned objectives and other related objectives, the technical solution provided in this application is as follows.

[0008] This application provides a Schottky contact superbarrier rectifier, comprising:

[0009] A cathode metal layer and a first conductivity type substrate layer and a first conductivity type drift region are sequentially stacked on the cathode metal layer;

[0010] A first groove is provided in the first conductivity type drift region, and a second conductivity type anode body region is provided in the first groove.

[0011] A second conductivity type low electron barrier germanium-silicon region is provided on the anode body region;

[0012] An anode metal layer and an oxide layer are disposed on the low electron barrier germanium-silicon region of the second conductivity type;

[0013] A first conductivity type low electron barrier germanium-silicon region is provided on the first conductivity type drift region;

[0014] The oxide layer is disposed on the first conductivity type low electron barrier germanium-silicon region;

[0015] A polycrystalline silicon layer of the first conductivity type is disposed on the oxide layer;

[0016] The anode metal layer is disposed on the first type of conductive polycrystalline silicon layer.

[0017] In one embodiment of the present invention, the oxide layer covers a portion of the second conductivity type low electron barrier germanium-silicon region and the first conductivity type low electron barrier germanium-silicon region.

[0018] In one embodiment of the present invention, the anode metal layer covers a portion of the second conductivity type low electron barrier germanium-silicon region and the first conductivity type polycrystalline silicon layer.

[0019] In one embodiment of the present invention, the anode metal layer is in contact with the second conductivity type low electron barrier germanium-silicon region, and a Schottky contact is formed at the contact point.

[0020] In one embodiment of the present invention, the anode metal layer and the second conductivity type low electron barrier germanium-silicon region are disposed on the anode body region of the second conductivity type.

[0021] In one embodiment of the present invention, the oxide layer is disposed on the first conductivity type drift region, and the oxide layer covers the second conductivity type low electron barrier germanium-silicon region and part of the first conductivity type drift region.

[0022] In one embodiment of the present invention, the anode metal layer is in contact with the second conductivity type anode body region and the second conductivity type low electron barrier germanium-silicon region, and a Schottky contact is formed at the contact point.

[0023] This application provides a Schottky contact super-barrier rectifier. This rectifier forms a low-electron-barrier structure based on an anode metal layer, a polysilicon layer of a first conductivity type, an oxide layer, and a germanium-silicon region of a second conductivity type. This low-electron-barrier structure serves as the anode structure of the rectifier. When the rectifier is forward-biased, electrons flow more easily from the cathode to the anode, resulting in a lower on-state voltage. Therefore, the rectifier can increase the oxide layer thickness without degrading the forward on-state voltage and reverse leakage current. By increasing the oxide layer thickness, the single-event gate-through characteristics of the Schottky contact super-barrier rectifier can be improved without degrading its basic electrical properties, thereby enhancing its resistance to single-event gate-through.

[0024] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:

[0026] Figure 1 A schematic cross-sectional view of a Schottky contact superbarrier rectifier shown as an exemplary embodiment of the present invention;

[0027] Figure 2 A schematic cross-sectional view of a superbarrier rectifier with an improved Schottky contact structure, shown as an exemplary embodiment of the present invention;

[0028] Figure 3 This is a comparison diagram showing the single-ion gate-through resistance characteristics of a Schottky contact superbarrier rectifier and a conventional Schottky contact superbarrier rectifier, illustrating an exemplary embodiment of the present invention.

[0029] Explanation of reference numerals in the attached figures: 1-Cathode metal layer, 2-Substrate layer of the first conductivity type, 3-Drift region of the first conductivity type, 4-Anode body region of the second conductivity type, 5-Oxide layer, 6-Polycrystalline silicon layer of the first conductivity type, 7-Anode metal layer, 10-Germanium-silicon region of the first conductivity type with low electron barrier, 11-Germanium-silicon region of the second conductivity type with low electron barrier. Detailed Implementation

[0030] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0031] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0032] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the invention. However, it will be apparent to those skilled in the art that embodiments of the invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the invention.

[0033] With the development of power integrated circuits, the development of power semiconductor devices is booming. Power semiconductor rectifiers are an important type of semiconductor device, playing a crucial role in power supplies and power converters.

[0034] The Schottky Contact Super Barrier Rectifier (SSBR) emerged in this context, representing a new type of power semiconductor rectifier with excellent performance and a simple manufacturing process. It exhibits good performance in terms of low forward voltage, small reverse leakage current, and short reverse recovery time, making it a superior choice for power semiconductor rectifiers.

[0035] However, due to the thin gate oxide layer, traditional super barrier rectifiers are prone to single-event gate penetration when operating in the environment of heavy ion rays, which can lead to permanent damage to the device and result in insufficient reliability of single-event gate penetration performance.

[0036] like Figure 1 As shown, in an exemplary embodiment, a Schottky contact superbarrier rectifier includes:

[0037] Cathode metal layer 1 and first conductivity type substrate layer 2 and first conductivity type drift region 3 are stacked sequentially on cathode metal layer 1;

[0038] A first groove is provided in the first conductivity type drift region 3, and a second conductivity type anode body region 4 is provided in the first groove;

[0039] A second conductivity type low electron barrier germanium-silicon region 11 is provided on the anode body region 4 of the second conductivity type.

[0040] An anode metal layer 7 and an oxide layer 5 are disposed on the second conductivity type low electron barrier germanium-silicon region 11.

[0041] A first conductivity type low electron barrier germanium-silicon region 10 is provided on the first conductivity type drift region 3.

[0042] An oxide layer 5 is disposed on the first conductivity type low electron barrier germanium-silicon region 10;

[0043] A polysilicon layer 6 of the first conductivity type is disposed on the oxide layer 5;

[0044] An anode metal layer 7 is disposed on the polycrystalline silicon layer 6 of the first conductivity type.

[0045] It should be emphasized that the first conductivity type substrate layer 2 and the first conductivity type polycrystalline silicon layer 6 are heavily doped, while the first conductivity type drift region 3 and the first conductivity type low electron barrier germanium-silicon region 10 are lightly doped.

[0046] Specifically, the main material of the Schottky contact superbarrier rectifier is silicon, and the doping concentration of the lightly doped first conductivity type drift region 3 ranges from 1×10⁻⁶. 15 cm -3 Up to 8×10 15 cm -3 The doping concentration of the heavily doped first conductivity type gate polysilicon layer 6 ranges from 1 × 10⁶. 20 cm -3 Up to 1×10 21 cm -3 The oxide layer 5 is made of silicon dioxide, and its thickness ranges from 10 nm to 30 nm. The doping of the second conductivity type anode region 4 employs a reverse P-region doping method. The peak doping concentration in the second conductivity type anode region 4 is located 0.3 μm-0.6 μm below the contact point with the anode metal layer 7, and the doping concentration ranges from 2.5 × 10⁻⁶. 13 cm -2 Up to 4.5×10 13 cm -2 .

[0047] The oxide layer 5 and the second conductivity type low electron barrier germanium-silicon region 11, together with the first conductivity type low electron barrier germanium-silicon region 10, constitute a low electron barrier structure. The low electron barrier structure is made of SiGe material, and the molar composition of Ge element in SiGe material ranges from 0 to 1. The doping concentration of the second conductivity type low electron barrier germanium-silicon region 11 ranges from 2.5 × 10⁻⁶. 13 cm -2 Up to 4.5×10 13 cm -2 The doping concentration in the lightly doped first conductivity type low electron barrier germanium-silicon region ranges from 1 × 10⁻⁶. 15 cm -3 Up to 8×10 15 cm -3 .

[0048] The anode metal layer 7, the first conductivity type polycrystalline silicon layer 6, the oxide layer 5, and the second conductivity type low electron barrier germanium-silicon region 11 constitute the anode structure of the Schottky contact super barrier rectifier; the cathode metal layer 1 constitutes the cathode structure of the Schottky contact super barrier diode, and the cathode metal layer 1 is in contact with the first conductivity type substrate layer 2.

[0049] In detail, such as Figure 1 As shown, oxide layer 5 covers the second conductivity type low electron barrier germanium-silicon region 11 and the first conductivity type low electron barrier germanium-silicon region 10.

[0050] More in detail, such as Figure 1 As shown, the anode metal layer 7 covers the second conductivity type low electron barrier germanium-silicon region 11 and the first conductivity type polycrystalline silicon layer 6.

[0051] In detail, such as Figure 1 As shown, the anode metal layer 7 is in contact with the second conductivity type low electron barrier germanium-silicon region 11, and a Schottky contact is formed at the contact point.

[0052] like Figure 1 As shown, when the Schottky contact super barrier rectifier is forward-biased, the oxide layer 5 and the second conductivity type low electron barrier germanium-silicon region 11 and the first conductivity type low electron barrier germanium-silicon region 10 together constitute a low electron barrier structure and form a current conduction channel at the contact.

[0053] In detail, such as Figure 2 As shown, an anode metal layer 7 and a second conductivity type low electron barrier germanium-silicon region 11 are disposed on the anode body region 4 of the second conductivity type.

[0054] More in detail, such as Figure 2 As shown, an oxide layer 5 is disposed on the first conductivity type drift region 3, and the oxide layer 5 covers the second conductivity type low electron barrier germanium-silicon region 11 and part of the first conductivity type drift region 3.

[0055] More in detail, such as Figure 2 As shown, the anode metal layer 7 contacts the second conductivity type anode body region 4 and the second conductivity type low electron barrier germanium-silicon region 11, forming a Schottky contact at the contact point. Specifically, the anode metal layer 7 contacts the second conductivity type anode body region 4 and the second conductivity type low electron barrier germanium-silicon region 11, etching the original second conductivity type low electron barrier germanium-silicon region 11 to a depth of 0.2μm-0.5μm. By etching part of the second conductivity type low electron barrier germanium-silicon region 11, the area of ​​the Schottky contact is increased. The oxide layer 5, the second conductivity type low electron barrier germanium-silicon region 11, and the first conductivity type drift region 3 together constitute a low electron barrier structure. Due to the change in Schottky, a stronger current channel is formed at the Schottky contact when the Schottky contact super-barrier rectifier is in positive phase conduction.

[0056] like Figure 3As shown, the Schottky contact superbarrier rectifier provided by the present invention has a smaller peak electric field in oxide layer 5 compared to the prior art Schottky contact superbarrier rectifier, and has better resistance to single-particle gate penetration.

[0057] This application provides a Schottky contact super-barrier rectifier. This rectifier forms a low-electron-barrier structure based on an anode metal layer, a polysilicon layer of a first conductivity type, an oxide layer, and a germanium-silicon region of a second conductivity type. This low-electron-barrier structure serves as the anode structure of the rectifier. When the rectifier is forward-biased, electrons flow more easily from the cathode to the anode, resulting in a lower on-state voltage. Therefore, the rectifier can increase the oxide layer thickness without degrading the forward on-state voltage and reverse leakage current. By increasing the oxide layer thickness, the single-event gate-through characteristics of the Schottky contact super-barrier rectifier can be improved without degrading its basic electrical properties, thereby enhancing its resistance to single-event gate-through.

[0058] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A Schottky contact superbarrier rectifier, characterized in that, include: A cathode metal layer and a first conductivity type substrate layer and a first conductivity type drift region are sequentially stacked on the cathode metal layer; A first groove is provided in the first conductivity type drift region, and a second conductivity type anode body region is provided in the first groove. A second conductivity type low electron barrier germanium-silicon region is provided on the anode body region; An anode metal layer and an oxide layer are disposed on the low electron barrier germanium-silicon region of the second conductivity type; A first conductivity type low electron barrier germanium-silicon region is provided on the first conductivity type drift region; The oxide layer is disposed on the first conductivity type low electron barrier germanium-silicon region; A polycrystalline silicon layer of the first conductivity type is disposed on the oxide layer; The anode metal layer is disposed on the first type of conductive polycrystalline silicon layer; The oxide layer covers a portion of the second conductivity type low electron barrier germanium-silicon region, and the anode metal layer contacts the second conductivity type low electron barrier germanium-silicon region, forming a Schottky contact at the contact point.

2. The Schottky contact superbarrier rectifier according to claim 1, characterized in that, The oxide layer also covers the first conductivity type low electron barrier germanium-silicon region.

3. The Schottky contact superbarrier rectifier according to claim 2, characterized in that, The anode metal layer covers a portion of the second conductivity type low electron barrier germanium-silicon region and the first conductivity type polycrystalline silicon layer.

4. The Schottky contact superbarrier rectifier according to claim 1, characterized in that, The anode metal layer and the second conductivity type low electron barrier germanium-silicon region are disposed on the anode body region.

5. The Schottky contact superbarrier rectifier according to claim 4, characterized in that, The oxide layer is disposed on the first conductivity type drift region, and the oxide layer covers the second conductivity type low electron barrier germanium-silicon region and part of the first conductivity type drift region.

6. The Schottky contact superbarrier rectifier according to claim 4, characterized in that, The anode metal layer contacts the anode body region of the second conductivity type and the germanium-silicon region of the second conductivity type with low electron barrier, and a Schottky contact is formed at the contact point.

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