NONVOLATILE MEMORY CELL WITH TRENCH HAVING FIRST PART DEEPER THAN SECOND PART, ARRAY OF MEMORY CELL AND MANUFACTURING METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a nonvolatile floating gate memory cell made by a trench of a semiconductor substrate. SOLUTION: A nonvolatile memory cell is made in a substrate of a substantially single crystalline semiconductive material having a first conductive type and a surface. The trench resides on the surface, and extends over a first depth and a second depth deeper than the first depth in the substrate. The trench is provided with: a first side wall along the trench extending to the first depth; a second side wall along the trench extending from the first depth to the second depth; and a bottom wall along a bottom face of the trench. A first region of a second conductive type resides in a substrate along the bottom face of the trench. A second region of the second conductive type resides in a substrate along the front surface of the trench. COPYRIGHT: (C)2006,JPO&NCIPI