| 摘要 |
PURPOSE:To prolong a time of retention of a memory by a method wherein the diffusion of a carrier caught by a trap in a silicon nitride film is prevented by changing the surface of the silicon nitride film of an MNOS element into a silicon oxide film in an oxidizing atmosphere of high pressure. CONSTITUTION:After the silicon oxide film 102 about 1.0mu thick is formed on a silicon substrate 101, impurity is diffused through holes 103 and 103' for diffusion and thereby a source and a drain 104 and 105 are formed. Next, the thick silicon oxide film in a gate part being removed, a thin silicon oxide film 106 of several tens Angstrom and a silicon nitride film 107 several hundreds Angstrom thick are formed. Consecutively, the surface of the silicon nitride film 107 is oxidized with high pressure in the atmosphere of steam of 9 atmospheric pressure, whereby a silicon oxide film of about 100Angstrom is formed. Finally, Al is evaporated through contact holes 109 and 110 being opened, patterning is conducted, and thus electrodes 111, 112 and 113 are formed. |
