SEMICONDUCTOR MEMORY ARRAY OF FLOATING GATE MEMORY CELLS EQUIPPED WITH EMBEDDED FLOATING GATE AND MOUNTAIN-SHAPED CHANNEL REGION

摘要

PROBLEM TO BE SOLVED: To provide an array of floating gate memory cells having a trench formed in the surface of a semiconductor substrate. SOLUTION: A source region is formed beneath a trench, a drain region is formed along the surface of a substrate, and a channel region between them includes a first part stretching vertically along the side wall of the trench and a second part stretching horizontally along the surface of a substrate. A floating gate is arranged in the trench contiguously to the first part of the channel region while being isolated therefrom. A control gate is arranged on the second part of the channel region while being isolated therefrom. Side wall of the trench intersects the surface of the substrate at an acute angle to form a sharp edge. The second part of the channel region stretches from a second region toward the sharp edge and the floating gate to define a passage for programming the floating gate with electrons by high temperature electron injection. COPYRIGHT: (C)2005,JPO&NCIPI