Solar-blind AlGaN ultraviolet photodetector and preparation method thereof

A method for preparing the solar-blind AlGaN UV photodetector, characterized in that the method comprises the following steps:

• growing the following layers sequentially on the silicon substrate:
• an undoped N-polar plane AlN buffer layer, a carbon-doped N-polar plane AlN layer, a carbon-doped N-polar plane composition-graded AlyGa1-yN layer, and an undoped N-polar plane AlxGa1-xN layer, where x=0.5-0.8, and y=0.75-0.95, thus obtaining an UV photodetector epitaxial wafer, and then processing the wafer;
• performing photolithography on the processed UV photodetector epitaxial wafer to obtain an isolation pattern, then etching the UV photodetector epitaxial wafer to obtain a groove along the isolation pattern, and then placing the UV photodetector epitaxial wafer in a plasma-assisted chemical vapor deposition device to deposit a SiNz passivation layer in the groove, where z=1.33-1.5;
• etching the exposed SiNz on the UV photodetector epitaxial wafer away by a wet etching method, and then processing the wafer;
• performing photolithography on one side of the undoped N-polar plane AlxGa1-xN layer through mask alignment to obtain an insulating layer pattern thereon, then placing the UV photodetector epitaxial wafer prepared in an electron beam evaporation device to evaporation-deposit an isolating layer thereon, and then processing the UV photodetector epitaxial wafer with the prepared insulating layer;
• performing photolithography on the insulating layer and oppositely on the undoped N-polar plane AlxGa1-xN layer through mask alignment, respectively, thus obtaining the pattern of the ohmic contact electrode;
• then placing the UV photodetector epitaxial wafer in the electron beam evaporation device to evaporation-deposit an ohmic contact electrode metal, thus obtaining the ohmic contact electrode;
• and then processing the UV photodetector epitaxial wafer;
• and
• performing photolithography through mask alignment on the ohmic contact electrode metal on the insulating layer, and on the side surface of the insulating layer and the ohmic contact electrode, as well as on the undoped N polar plane AlxGa1-xN layer, thus obtaining the pattern of the Schottky contact electrode;
• and then covering the pattern of the Schottky contact electrode sufficiently uniformly with a Schottky contact electrode material, heating, and standing to shape to obtain the solar-blind AlGaN UV photodetector.