A high density 4M DRAM process using folded bitline adaptive side-wall isolated capacitor (FASIC) cell

Submicron CMOS process technologies for a high density 4M DRAM are presented emphasizing a cell area reduction to 10.9 um2 using a newly proposed FASIC cell. Two novel techniques were developed to realize the new cell structure. The oblique ion implantation technique can make a shallow impurity doping into the side wall and the local oxidation at the side wall technique makes the half-contact/cell architecture on the peripheral trench type cell.