阅读说明：本技术 一种双结型SiC器件及其制备方法 (Double-junction SiC device and preparation method thereof ) 是由 张伟 汤乃云 叶怀宇 张国旗 于 2019-09-17 设计创作，主要内容包括：本发明涉及一种双结型SiC器件及其制备方法,包括以下步骤：1)N型SiC衬底上形成P型SiC层；2)P型SiC层上形成N型SiC层；3)在所述N型SiC衬底底部设置第一电极,刻蚀所述N型SiC层并沉积第三电极；4)刻蚀所述N型SiC层和P型SiC层并沉积第2电极；5)N型SiC层上生长荧光层；6)金属封装荧光层和部分N型SiC层形成金属层。7)在所述金属层的内侧涂覆光反射层；8)在所述金属层顶部开辐射窗口。与现有技术相比,本发明采用两个PN结并联,光电压现象较为显著,探测灵敏度高。同时器件使用了荧光材料做为转换材料,增加可探测光子数目,并使用金属反射层提高光收集效率,探测灵敏度进一步增强。(The invention relates to a double-junction SiC device and a preparation method thereof, comprising the following steps: 1) forming a P-type SiC layer on the N-type SiC substrate; 2) forming an N-type SiC layer on the P-type SiC layer; 3) arranging a first electrode at the bottom of the N-type SiC substrate, etching the N-type SiC layer and depositing a third electrode; 4) etching the N-type SiC layer and the P-type SiC layer and depositing a No. 2 electrode; 5) growing a fluorescent layer on the N-type SiC layer; 6) the metal-encapsulated fluorescent layer and a portion of the N-type SiC layer form a metal layer. 7) Coating a light reflection layer on the inner side of the metal layer; 8) and opening a radiation window on the top of the metal layer. Compared with the prior art, the invention adopts two PN junctions in parallel connection, the photovoltage phenomenon is more obvious, and the detection sensitivity is high. Meanwhile, the device uses a fluorescent material as a conversion material, the number of detectable photons is increased, the light collection efficiency is improved by using a metal reflecting layer, and the detection sensitivity is further enhanced.)

1. A preparation method of a double-junction SiC device is characterized by comprising

1) Forming a P-type SiC layer on the N-type SiC substrate through doping;

2) forming an N-type SiC layer on the P-type SiC layer through doping;

3) depositing a first electrode at the bottom of the N-type SiC substrate, etching the N-type SiC layer and depositing a third electrode;

4) etching the N-type SiC layer and the P-type SiC layer and depositing a second electrode;

5) growing a fluorescent layer on the N-type SiC layer;

6) the metal-encapsulated fluorescent layer and a portion of the N-type SiC layer form a metal layer.

7) Coating a reflecting layer on the inner side of the metal layer;

8) a radiation window is formed on top of the metal layer.

2. The method for producing a double junction type SiC device according to claim 1, characterized in that: in the step 1), the thickness of the N-type SiC substrate is more than or equal to 100 mu m, and the doping mode is ion implantation or thermal diffusion.

3. The method for producing a double junction type SiC device according to claim 2, characterized in that: in the step 1), the doping element is B or Al, and the doping concentration is more than or equal to 5 multiplied by 10¹⁵cm^-3。

4. The method for producing a double junction type SiC device according to claim 1, characterized in that: in the step 2), the thickness of the P-type SiC layer is more than or equal to 1 mu m; the thickness of the N-type SiC layer is more than or equal to 1 mu m; the doping mode is ion implantation or thermal diffusion.

5. The method for producing a double junction type SiC device according to claim 4, characterized in that: in the 2) above, the doping element is P or As, and the doping concentration is not less than 5 multiplied by 10¹⁵cm^-3。

6. The method for producing a double junction type SiC device according to claim 1, characterized in that: in the step 5), the thickness of the fluorescent layer is more than or equal to 50 nm; the fluorescent layer material is any one of alkaline earth metal sulfide, aluminate, oxadiazole and derivatives thereof, triazole and derivatives thereof, rhodamine and derivatives thereof or coumarin derivatives.

7. The method for producing a double junction type SiC device according to claim 5, characterized in that: the alkaline earth metal sulfide includes ZnS or CaS; the aluminate includes SrAl₂O₄，CaAl₂O₄Or BaAl₂O₄。

8. The method for producing a double junction type SiC device according to claim 1, characterized in that: the material of the reflecting layer is Ag or Au; the thickness of the reflecting layer is more than or equal to 1 mu m.

9. The method for producing a double junction type SiC device according to claim 1, characterized in that: the manner of forming the radiation window in 8) is etching and welding.

10. A double junction SiC device prepared according to the method of claims 1-9, the device comprising a nuclear radiation detector.

Technical Field

The invention belongs to the technical field of semiconductors, and particularly relates to a double-junction SiC device and a preparation method thereof.

Background

The nuclear power plant is easy to cause that the local radiation dose exceeds the standard, the detection is required to be carried out in time, and high requirements are provided for the response speed and the sensitivity of a radiation detection device. The ray detector based on the semiconductor device is popular in research of novel detectors due to the advantages of small volume, low power consumption, high sensitivity, capability of being integrated with an electronic circuit on the same chip and capability of working under the condition of zero bias voltage. At present, monocrystalline silicon, amorphous silicon and polycrystalline silicon are used as materials of a semiconductor layer used by a nuclear detection device, but the materials have narrow forbidden band width and relatively small atomic number and density, so that the nuclear detection device is sensitive to radiation damage, needs refrigeration and is used at low temperature, and the use of the nuclear detection device in the high-radiation field is restricted. Meanwhile, the conventional detector structure is generally a single PN junction structure, the output photovoltage is low, the photon receiving efficiency is low, and therefore the detection sensitivity is low.

Disclosure of Invention

In order to overcome the problems, the invention provides a double-junction SiC device and a preparation method thereof, which comprises the following steps of

1) Forming a P-type SiC layer on the N-type SiC substrate through doping;

2) forming an N-type SiC layer on the P-type SiC layer through doping;

3) depositing a first electrode at the bottom of the N-type SiC substrate, etching the N-type SiC layer and depositing a third electrode;

4) etching the N-type SiC layer and the P-type SiC layer and depositing a second electrode;

5) growing a fluorescent layer on the N-type SiC layer;

6) the metal-encapsulated fluorescent layer and a portion of the N-type SiC layer form a metal layer.

7) Coating a reflecting layer on the inner side of the metal layer;

8) a radiation window is formed on top of the metal layer.

Further, in the step 1), the thickness of the N-type SiC substrate is more than or equal to 100 μm, and the doping mode is ion implantation or thermal diffusion.

Further, in the step 1), the doping element is B or Al, and the doping concentration is more than or equal to 5 multiplied by 10¹⁵cm^-3。

Further, in the step 2), the thickness of the P-type SiC layer is more than or equal to 1 μm; the thickness of the N-type SiC layer is more than or equal to 1 mu m; the doping mode is ion implantation or thermal diffusion.

Further, in the step 2), the doping element is P or As, and the doping concentration is more than or equal to 5 multiplied by 10¹⁵cm^-3。

Further, in the step 5), the thickness of the fluorescent layer is more than or equal to 50 nm; the fluorescent layer material is any one of alkaline earth metal sulfide, aluminate, oxadiazole and derivatives thereof, triazole and derivatives thereof, rhodamine and derivatives thereof or coumarin derivatives.

Further, the alkaline earth metal sulfide includes ZnS or CaS; the aluminate includes SrAl₂O₄，CaAl₂O₄Or BaAl₂O₄。

Further, the material of the reflecting layer is Ag or Au; the thickness of the reflecting layer is more than or equal to 1 mu m.

Further, the manner of forming the radiation window in 8) is etching and welding.

The double-junction SiC device prepared by the method comprises a nuclear radiation detector.

Compared with the prior art, the invention has the advantages that:

(1) the double-junction SiC radiation detection device prepared based on the wide-bandgap SiC material has the advantage of high output photovoltage compared with the traditional single-PN-junction silicon device by utilizing the advantage of parallel connection of two PN junctions;

(2) the SiC material has the characteristics of high thermal conductivity, high response speed, high temperature resistance, radiation resistance, good chemical stability and the like, and the integration level of a detector system is simplified. The double-junction detector prepared based on the wide bandgap SiC material has the advantages of high detection efficiency, high sensitivity, high output voltage, high temperature resistance, radiation resistance, good chemical stability and the like. The SiC material of the same worker has larger forbidden bandwidth, high breakdown electric field and high carrier saturation mobility;

(3) meanwhile, the fluorescent material integrated on the SiC material is used as a conversion material, and can generate a large amount of ultraviolet light under the excitation of external irradiation. Meanwhile, the light reflecting layer is used for collecting photons, the number of detectable photons is increased, and the detection sensitivity is enhanced.

Drawings

FIG. 1 is a schematic structural diagram of a double-junction SiC device provided in embodiments 1 to 3 of the present invention

An N-type SiC substrate 1, a P-type SiC layer 2, an N-type SiC layer 3, a fluorescent material layer 4, a metal packaging layer 5, a light reflection layer 6, a radiation window 7, a first electrode 8, a second electrode 9 and a third electrode 10

Detailed Description

The embodiments herein and the various features and relevant details of the embodiments described below in connection with the specific examples are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Conventional processes well known in semiconductor processing may be used in fabricating the structure. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples herein should not be construed as limiting the scope of the embodiments herein.

It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the drawings only show the components related to the present invention rather than the number, shape and size of the components in actual implementation, and the type, number and ratio of the components in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.