Semiconductor nonvolatile memory

Abstract

Abstract PURPOSE:To inject electrons efficiently to a floating gate at low voltage by forming an N type impurity region in a self-alignment manner with an insulating film when the threshold voltage of a first channel region is brought to proper magnitude and programmed. CONSTITUTION:N<+> type source region 12 and drain region 13 are formed to the surface of a P type semiconductor substrate 11 at an interval. Channel regions L1, L2 and L3 are formed in series between the regions 12, 13. There is a selective gate electrode 15 on the region L1 through a selective gate insulating film 14, there is a floating gate electrode 17 on the region L2 through an insulating film 16, and an insulating gate 19 is shaped on the electrode 17 through an insulating film 18. There is a thick insulating film 20 formed at the same time as the film 18 on the region L2. A region 21 in which an N type impurity is diffused in a self-alignment menner with the film 20 through ion implantation is formed near the region L1. Accordingly, electrons can be injected efficiently to the electrode 17 at low voltage.

Inventors

• 👤 Yukihiro Imura
• 👤 行宏 井村

Bibliographic Details