| 摘要 |
PURPOSE:To avoid the remaining of an evaporated metallic film in a mesa groove on an Si substrate, and to improve the reliability and yield of the device by coating the surface of the groove with a glass protective film and burying the groove by a photo- resist liquid. CONSTITUTION:P layers 2, 3 are formed through diffusion from both surfaces of an N type Si substrate 1, N layers are shaped to the P layer 3, and the mesa grooves 11 penetrating a P-N junction are molded while using an SiO2 6 as a mask. The grooves 11 are coated selectively with BSG powder through an electrophoresis method, the powder is melted, and the protective films 12 are formed. A stainless mask 13 is located on the surface, a photo-resist 14 is applied and the grooves 11 are buried, and the mask 13 is removed. The surfaces are coated with a photo-resist 15 again, windows 16-18 are shaped selectively, and a metallic film 22 is evaporated. When the whole is sintered at a high temperature and an adhesive tape is pasted and exfoliated, the excessive metallic films on the mesa grooves and between a gate and a cathode are simply removed, and electrodes 19-21 are molded. According to this constitution, the strength of the substrate is increased because the photo-resist buries the mesa grooves, remaining no metallic films in the grooves, yield is improved, and the device, characteristics thereof are stable and highly reliable, can be mass-produced. |
