SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD OF THE SAME

PROBLEM TO BE SOLVED: To provide a vertical MOS transistor having a small sized trench structure.SOLUTION: In a semiconductor device, by forming an STI oxide film on a substrate among a series of trenches formed at regular intervals and in a silicon surface region where a source high-concentration diffusion layer is to be formed later, and removing the STI oxide film after forming the trenches to form a region lower than a surrounding surface, silicides provided on a gate electrode buried in trench grooves of a vertical MOS transistor having a trench-structure with side spacers, on the substrate, and on the source high-concentration diffusion layer can be isolated from each other. Accordingly, size reduction of the trench for area reduction and high drive capability of the semiconductor device can be achieved.