TW243552B - Fabricating method for flash EEPROM - Google Patents

Abstract

A fabricating method for flash EEPROM with high electron tunneling efficiency includes: 1. growing one gate oxide on the first conductive semiconductor or the first conductive well area, and defining the source/drain region through tunneling oxide mask, then implanting the second conductive dopant ion with high density to form buried the second conductive area; 2. doping the first polysilicon, and doping dopant, then etching through mask, making the first polysilicon overlay only on the buried second conductive area and connect with the buried second conductive area in short circuit, then removing mask; 3. growing one polysilicon oxide through thermal oxidization and making the interface between the first polysilicon and polysilicon oxidization form many needle protuberance, then depositing the second polysilicon and doping dopant and through mask etching to form floating gate, then implanting the second conductive dopant ion with high density to from source/drain region; 4. depositing one intermediate insulating layer as the electric separation between two polysilicon, and depositing the third polysilicon, doping dopant and through mask etching to form control gate.