Semiconductor memory device and manufacturing method thereof

Abstract

The present disclosure relates to a semiconductor memory, device and a method of forming a semiconductor memory device. The method of manufacturing a semiconductor memory device, includes forming a tunnel insulation layer and a floating gate on a semiconductor substrate of an active region, forming a trench in the semiconductor substrate of an isolation region, forming, in the trench, a sacrificial layer having an upper surface positioned higher than a surface of the semiconductor substrate, forming a capping layer over the sacrificial layer, and forming an air gap by removing the sacrificial layer without removing the capping layer.

Dependencies are inferred from the claim text.