Ultraviolet Detector and Preparation Method Therefor

A method comprising:

• preparing a first semiconductor epitaxial wafer or a second semiconductor epitaxial wafer for an ultraviolet detector, wherein the first semiconductor epitaxial wafer comprises a substrate, a first epitaxial layer and a second epitaxial layer in an order from bottom to top, the second semiconductor epitaxial wafer comprises a substrate, a first epitaxial layer, a second epitaxial layer and a third epitaxial layer in an order from bottom to top;
• wherein the first epitaxial layer of the first semiconductor epitaxial wafer and the first epitaxial layer of the second semiconductor epitaxial wafer being a heavily doped epitaxial layer, the second epitaxial layer of the first semiconductor epitaxial wafer and the second epitaxial layer of the second semiconductor epitaxial wafer being a lightly doped epitaxial layer, or the second epitaxial layer of the first semiconductor epitaxial wafer and the second epitaxial layer of the second semiconductor epitaxial wafer being a double-layer or multi-layer structure comprising at least one lightly doped epitaxial layer and at least one heavily doped epitaxial layer;
• and the third epitaxial layer being a heavily doped epitaxial layer;
• for the first semiconductor epitaxial wafer, preparing a mask layer on a surface of the second epitaxial layer, coating a photoresist on the mask layer, photoetching on the photoresist and the mask layer to form a graphical ion implantation window, performing ion implantation through the graphical ion implantation window to form a graphical ohmic contact layer, and removing the photoresist and the mask layer which have been photoetched;
• for the second semiconductor epitaxial wafer, preparing a mask layer on a surface of the third epitaxial layer, coating a photoresist on the mask layer, photoetching on the photoresist and the mask layer to form a graphical etching mesa, etching an area outside the graphical etching mesa on the mask layer to the second epitaxial layer to form a graphical ohmic contact layer, and removing the photoresist and the mask layer which have been photoetched;
• isolating the first semiconductor epitaxial wafer or the second semiconductor epitaxial wafer by utilizing a mesa etching or ion implantation method to form an active region;
• and
• performing metal evaporating and annealing on the active region to form a first metal electrode layer;
• and
• wherein a surface area of the first metal electrode layer is not larger than a surface area of the graphical ohmic contact layer, the surface area of the first metal electrode layer is a connected area, a surface graphic of the first metal electrode layer corresponds to a surface graphic of the graphical ohmic contact layer, the surface graphic of the graphical ohmic contact layer includes a window shape or an array shape, when the surface graphic of the graphical ohmic contact layer is the window shape, the surface graphic of the first metal electrode layer is the window shape, and when the surface graphic of the graphical ohmic contact layer is the array shape, the surface graphic of the first metal electrode layer is the array shape.