Method for forming vertical channels in split-gate flash memory cell

Abstract

A method of forming a vertical memory split gate flash memory device on a silicon semiconductor substrate is provided by the following steps. Form a floating gate trench hole in the silicon semiconductor substrate, the trench hole having trench surfaces. Form a tunnel oxide layer on the trench surfaces, the tunnel oxide layer having outer surfaces. Form a floating gate electrode layer filling the trench hole on the outer surfaces of the tunnel oxide layer. Form source/drain regions in the substrate self-aligned with the floating gate electrode layer. Pattern the floating gate electrode layer by removing the gate electrode layer from the drain region side of the trench hole. Form a control gate hole therein. Form an interelectrode dielectric layer over the top surface of the floating gate electrode, and over the tunnel oxide layer. Form a control gate electrode over the interelectrode dielectric layer over the top surface of the floating gate electrode and extending down into the control gate hole in the trench hole.

Dependencies are inferred from the claim text.