| 摘要 |
PURPOSE:To increase memory keeping characteristic by heat treatment in hydrogen atomosphere after forming silicon nitride film, in the production of MNOS fixed memory utilizing two layer films of silicon dixode and silicon nitride as gate insulation film. CONSTITUTION:Gate insulation film consisting of SiO2 film 4 and Si3N4 film 5 is formed on semiconductor basic plate of Si and the like and gate electrode 6 is selectively formed thereon. The gate electrode is formed from multicristal silicon or metal having high melting point and then by masking gate electrode and accomplishing selfalign so that source and drain 7 may be formed. Next after covering whole surface with protective film such as phosphorous glass, electrode 10 is formed. After forming the silicon nitride film 5, by heat treatment at more than 700 deg.C in hydrogen atmosphere, surface level between Si basic plate and SiO2 film is lowered and by increasing elective conductivity, memory keeping characteristic can be improved.
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