Nonvolatile semiconductor memory

Patent Granted This invention provides a nonvolatile semiconductor memory element, which can realize an improvement in insulating properties of an insulator around a floating gate and a reduction in proportion of oxidized metal ultrafine particles in the floating gate, and a process for producing the same. The production process is a process for producing a nonvolatile semiconductor memory element comprising a floating gate comprising a hardly oxidizable substance, which is an element having a Gibbs' oxide formation free energy in the range of 0 C to 1200 C and higher than Si, and an insulator surrounding the periphery of the floating gate and formed of an oxide of an easily oxidizable substance of which the Gibbs' oxide formation free energy is equal to or lower than Si.