| 摘要 |
PURPOSE:To prevent a semiconductor substrate from cracking by forming one conductivity type of once formed high density impurity region without mechanical polishing of a different conductivity type high density impurity region with the other conductivity type diffusing source film of higher density than the one conductivity type. CONSTITUTION:A diffusing source film 22 of the back surface side of a semiconductor substrate 21 is, for example, removed, and a P-type conductive type diffusing source film 24 is formed on the high density impurity region 23 of the exposed back surface side with a solution diluted with ethylene glycol with boride anhydride. Then, it is heat treated at 1,250 deg.C for approx. 20hr to convert the region 23 to a P-type conductivity type high density impurity 25. Subsequently, the films 22, 24 are removed, anode and cathode of the prescribed pattern are formed to obtain a mesa type diode. |
