TRENCH TYPE EPROM CELL AND FARICATING METHOD THEREOF

摘要

The method for increasing the integration ratio of the elements comprises the steps of: a) forming an N- layer (2) with low density and N+ layer (3) with high density for common source on the bottom face of a P type substrate (1); b) forming an N+ region (7) with high density for drain and a P+ region (6) with high density on the upper face of the substrate; c) forming a buried oxide layer (8) on the N+ region for drain; d) forming a trench (9) and the first insulation layer (10) on it; and e) forming a floating gate (11A), the second insulation layer (12) and a control gate (13) on the first insulation and the buried oxide layers. The channel region is formed on the substrate by the voltage of the control gate.