| 摘要 |
PURPOSE:To reduce cracking defects and obtain an excellent ohmic contact by a method wherein an Au layer containing Sb is formed on a silicon substrate, a layer of metal such as Ti is formed on it and another layer of metal such as Ni is formed on the first metal layer and then this system is subjected to heat treatment at a specific temperature range. CONSTITUTION:An epitaxial substrate 1 is employed and subjected to a predetermined diffusion process to form a base layer 3 and an emitter layer 2. At the final stage of the diffusion process, the wafer is polished to have a predetermined thickness. An Au layer 7 containing Sb is formed by evaporation or sputtering and a metal layer 6 made of Ti or of one metal or combination of two or more metals among Mo, W and Ta is formed as a stopper against Sb. Further, a metal film 5 made of one metal or combination of two ore more metals from among Ni, Cu, Ag and Au is formed on the first metal layer 6. This system is subjected to heat treatment at the temperature not less than 350 deg.C and not more than 500 deg.C to make an ohmic contact. |
