Silicon carbide single crystal x-ray detector and preparation method

A preparation method for a silicon carbide single crystal X-ray detector, comprising the following steps:

• step 1:
• graphical AlN ion implantation barrier layers were prepared on upper and lower surfaces of a high resistive silicon carbide single crystal by photolithographic mask assistant deposition;
• the barrier layers were AlN ion implantation barrier layer a10, AlN ion implantation barrier layer b11 and AlN ion implantation barrier layer c12;
• a thickness of the barrier layer a10 was 10 nm to 10 μm, and a diameter of the barrier layer a10 was 50%˜90% of an edge length of a whole sample;
• a thickness of layer b11 is 10 nm˜15 μm, and an annular width accounts for 5%˜30% of the edge length of the whole sample;
• a thickness of layer c12 is 10 nm˜20 μm, covering all areas except for the a10 and b11;
• step 2:
• an n-type silicon carbide layer with transverse distribution of electron concentration and a p-type silicon carbide layer with transverse distribution of hole concentration were formed on an upper and lower surface of high-resistivity silicon carbide crystal by ion implantation and thermal annealing;
• a thickness of the n-type silicon carbide layer and the p-type silicon carbide layer was 10 nm to 10 μm;
• the n-type silicon carbide layer consisted of a high-electron concentration n-type silicon carbide layer and a low-electron concentration n-type silicon carbide layer, the low electron concentration n-type silicon carbide layer are arranged around the electron concentration n-type silicon carbide layer, an electron concentration of the high electron concentration n-type silicon carbide layer is 5.0×1016 cm−3˜5.0×1019 cm−3, and an electron concentration of the low electron concentration n-type silicon carbide layer is 5.0×1015 cm−3˜5.0×1018 cm−3;
• the p-type silicon carbide layer includes a high hole concentration p-type silicon carbide layer and a low hole concentration p-type silicon carbide layer, the low hole concentration p-type silicon carbide layer is arranged around the high hole concentration p-type silicon carbide layer, a hole concentration of the high hole concentration p-type silicon carbide layer is 5.0×1016 cm−3˜5.0×1019 cm−3, and a hole concentration of the low hole concentration p-type silicon carbide layer is 5.0×1015 cm−3˜5.0×1018 cm−3;
• step 3:
• protect the AlN layer on the upper surface of SiC crystal, wet etch the AlN layer on the lower surface of SiC crystal, deposit a silicon dioxide layer on the lower surface of SiC crystal, use photolithography mask technology and HF wet etching technology to open holes on a silicon dioxide protection layer, use photolithography mask technology, deposition technology and thermal annealing technology to prepare a p-type silicon carbide ohmic junction contact electrode;
• among them, the thickness of the silicon dioxide protective layer is 10 nm˜10 μm, the area of the open hole is the same as that of the high hole concentration p-type SiC layer 4, and a thickness of p-type SiC ohmic contact electrode is 10 nm˜15 μm, and a width is between an edge of the open hole and an edge of the lower surface of SiC single crystal;
• step 4:
• wet etching of the AlN layer on the surface of silicon carbide single crystal, depositing silicon dioxide protective layer on the surface of the silicon carbide single crystal;
• using photolithographic mask technology and HF wet etching technology to open holes on the silicon dioxide protective layer;
• using photolithographic mask technology and coating technology to prepare a patterned n-type silicon carbide ohmic contact electrode;
• using photolithographic mask technology, deposition technology and thermal annealing technology to fabricate of a graphical gold lead electrode;
• among them, a thickness of silicon dioxide protective layer is 10 nm˜10 μm;
• the area of open hole is the same as that of high electron concentration n-type silicon carbide layer;
• a thickness of n-type silicon carbide ohmic contact electrode is 10 nm˜15 μm, and the area of open hole is the same;
• a thickness of gold lead electrode is 10 nm˜10 μm, and a coverage area is between 10% of a surface edge of the high resistivity silicon carbide single crystal.