| 摘要 |
PURPOSE:To prevent deterioration of film quantity, by forming a secondary insulating film by low temperature oxidation after providing a high temperature heat oxide thin film between primary/secondary gate electrodes and a floating gate electrode. CONSTITUTION:A P<-> epitaxial layer surface on a P<-> substrate is subjected to dielectric insulation by means of a P layer 3 and an SiO2 layer 2 then primary poly Si gate electrodes 6, 7 are provided on a gate insulating film 5, which are thereafter covered with a thin layer insulation film 9 at a high temperature of 1000 deg.C. The insulating layer 5 is etched to form a gate insulating film 4 at a low temperature. Then a poly Si floating gate electrode 8 is selectively shaped to form an oxide film at about 800 deg.C. N<+> layers 10A, 10B are provided by ion implantation then laminated protective films 11 of SiO2 and PSG are laminated and burned at about 800 deg.C. Ion implantation is conducted again to N layers 10A, 10B to deepen the junction depth then annealing is applied at about 800 deg.C. Select wires 13, 14 of Al are provided thereafter, and the film 11 is covered with an SiO2 and Si3N4 laminated film. According to this constitution, a memory cell can be shaped without deteriorating the quality of gate insulating film. |
