Flash memory cell with vertically oriented channel

摘要

A vertical memory device on a silicon semiconductor substrate is formed by the following steps. Form an array of isolation silicon oxide structures on the surface of the silicon semiconductor substrate. Form a floating gate trench in the silicon semiconductor substrate between the silicon oxide structures in the array, the trench having trench sidewall surfaces. Dope the sidewalls of the floating gate trench with a threshold implant through the trench sidewall surfaces. Form a tunnel oxide layer on the trench sidewall surfaces, the tunnel oxide layer having an outer surface. Form a floating gate electrode in the trench on the outer surface of the tunnel oxide layer. Form source/drain regions in the substrate self-aligned with the floating gate electrode. Form an interelectrode dielectric layer over the top surface of the floating gate electrode. Form a control gate electrode over the interelectrode dielectric layer over the top surface of the floating gate electrode. Form a source line by the step of performing a self-aligned etch followed by a source line implant.