Abstract: A control gate is loaded with a negative voltage pulse and a source region is loaded with a positive constant voltage pulse while a drain region is at a floating state. More specifically, the absolute value of the voltage applied to the control gate is increased with time for a period from the start of a memory erasing action (the application of the pulse voltage) to 2 msec and then remains constant from 2 msec to the end of the memory erasing action. As the result, a potential difference between the source region and the control gate at the start of the memory erasing action is smaller than that at the end of the memory erasing action. This prevents the tunnel oxide layer from receiving a high electric field stress at the start of the memory erasing action, thus improving the write/erase endurance.

Abstract: On determining operating conditions for a nonvolatile semiconductor memory including a MOSFET (Metal Oxide Semiconductor Field-Effect Transistor), measurement is made, before completion of manufacture of the nonvolatile semiconductor memory and after completion of manufacture of the MOSFET, of characteristics of the MOSFET to obtain parameters which are used in simulating an operation of the nonvolatile semiconductor memory. By using the parameters, simulation of the operation of the nonvolatile semiconductor memory is executed to obtain a simulation result which is preferably a result relating to deterioration of operation characteristics of the nonvolatile semiconductor memory. The operating conditions for the nonvolatile semiconductor memory are obtained from the simulation result. The nonvolatile semiconductor memory may be an EEPROM (Electrically Erasable Programmable Read-Only Memory).

Abstract: The present invention provides a method for forming a silicon nitride film used for a capacitor dielectric film on a silicon substrate and a poly-silicon layer which comprises steps of forming a first thin silicon nitride film by a rapid thermal nitrogen process and forming a second silicon nitride film on the first thin silicon nitride film to a required thickness by LPCVD. In the LPCVD, a gas which reduces surface reactions is introduced to a growing surface of the silicon nitride film by a means different from a means supplying starting material gases of the silicon nitride film, so as to improve a break down voltage and leakage current of the capacitor silicon nitride film.

Abstract: A process simulation method and a process simulator are disclosed wherein a simulation for optimum process conditions for formation of a dielectric film for a capacitor by a chemical vapor deposition method is executed using a non-empirical reaction model.