Erasable electrically programmable read only memory cell using trench edge tunnelling

摘要

An electrically programmable read only memory cell formed in a face of a semiconductor substrate which includes a floating gate transistor having a floating gate and a control gate formed at least partially in a trench in the substrate. The trench has bottom corners sufficiently sharp so as to enhance the likelihood of tunnelling between corner regions of the trench and the floating gate over that between planar surface regions of the trench and floating gate.