Floating gate semiconductor memory

Abstract

Abstract PURPOSE:To improve the high speed and stability of a floating gate semiconductor memory by forming the same conductive type ion injection layer as a substrate on a part of the surface of the semiconductor under an insulating film in which electrons are injected from an electron injector, thereby decreasing the substrate density without deteriorating the electron injection efficiency. CONSTITUTION:Reverse conductive type source and drain regions 4, 3 are formed on one conductive type semiconductor substrate 1, and a floating gate 7 is partly formed through a gate insulating film thereon. The other part of the floating gate is formed larger than a control gate via a gate insulating film 8 on a control gate region 5 formed separately from the regions 3, 4. The same conductive type diffused layer 15 as the substrate and having higher density than the substrate 1 is formed under the film 8 in the vicinity of the region 5 between injector regions 6 and 5 separated from the region 5. Since the substrate density can be decreased without deteriorating the electron injection efficiency to the floating gate in this manner, the high speed and stability can be improved.

Inventors

• 👤 Yoshikazu Kojima

Bibliographic Details