Patent ID: 7820515

Claim:
A process for producing a nonvolatile semiconductor memory element having a mixed or laminated structure of a hardly oxidizable material composed of a hardly oxidizable element having a Gibbs' formation free energy for forming oxide higher than the Gibbs' formation free energy of Si for forming oxide under the same temperature condition at 1 atm and in a temperature range of from 0° C. to 1,200° C. and an oxide of an easily oxidizable material composed of an element having a Gibbs' formation free energy for forming oxide lower than the Gibbs' formation free energy of Si for forming oxide under the same temperature condition at 1 atm in the temperature range of from 0° C. to 1,200° C., and Si, the process comprising: forming a portion made of the hardly oxidizable material and a portion made of the oxide of the easily oxidizable material by a physical forming method; and carrying out a heat treatment in a mixed gas of an oxidizing gas functioning as an oxidizing agent and a reducing gas functioning as a reducing agent, wherein the mixture ratio of the oxidizing gas and the reducing gas and the temperature are controlled so that the hardly oxidizable material is reduced and the oxide of the easily oxidizable material is oxidized in a temperature range of from 0° C. to 1,200° C.