Method for manufacturing a semiconductor device

Abstract

Provided is a method for manufacturing semiconductor devices including channel trenches that are separated by isolation structures. According to the process, the substrate is etched to form isolation trenches after which a sidewall oxide layer, a liner nitride layer and a field oxide layer are subsequently formed on the substrate and in the isolation trenches. The substrate is then planarized to remove upper portions of the sidewall oxide layer, the liner nitride layer and the field oxide layer to expose surface portions of the substrate between adjacent isolation trench structures. Channel trenches are then formed in the exposed surface portions of the substrate leaving residual substrate regions adjacent the isolation trench structures. These residual substrate regions are then oxidized and removed to form improved second channel trenches for the formation of transistor regions.