| 摘要 |
PURPOSE:To enable a writing to a conductive state from a non-conductive state at a high rate of success by forming a p-n junction under a reverse bias state diffused and formed from the surface of a semiconductor substrate and a protective film of specific film thickness formed to the surface of the substrate on the junction section. CONSTITUTION:An n type impurity is diffused to the substrate 11 from the opening section of a field silicon oxide film 12, and an n type diffusion region 15 of approximately 0.5mum diffusion depth is formed. The substrate 11 and the diffusion region 15 are each wired properly so that the p-n junction section formed by the diffusion region 15 and the semiconductor substrate 11 is brought to a reverse bias state. The protective film 14 of a silicon oxide film is formed to the whole surface on the substrate 11 in film thickness of 0.5mum or more. When YAG pulse laser beams are irradiated selectively to said p-n junction section, they do not scatter when the thickness of the protective film 14 is made 0.5mum or more, a crystal is damaged, and stable junction leakage currents Il are obtained positively. when the diffusion depth of said n type diffusion region 15 reaches 1.0mum or more, the p-n junction is made difficult to be damaged through laser irradiation. |
