Flash memory cell

摘要

A novel flash memory cell has (a) a floating gate (37), an insulating layer (39) and a control gate (41) formed on a gate insulation layer (35) on a substrate (31); (b) side wall insulation layers (45, 52) formed on both sides of the floating gate (37) and the control gate (41); (c) sidewall conductive layers (53, 55) on the side wall insulation layers (45, 52); and (d) a source region (57) and a drain region (51, 58) formed in the substrate (31). Preferably, the sidewall conductive layers (53, 55) are polysilicon layers and the side wall insulation layers (45, 52) consist of phosphosilicate glass, borosilicate glass or borophosphosilicate glass. Also claimed is a flash memory cell production process which involves (i) successively forming a field insulation layer (33) and a gate oxide layer (35) on a substrate; (ii) forming a floating gate (37), an insulating layer (39) and a control gate (41) on the gate insulation layer (35); (iii) forming sidewall insulation layers (45, 52) on both sides of the floating gate (37) and the control gate (41) and then sidewall conductive layers (53, 55) on the side wall insulation layers (45, 52); and (iv) forming source and drain regions (57; 51, 58) in the substrate.