Recessed gate transistor with cylindrical fins

Abstract

A recessed gate transistor with cylindrical fins is disclosed. The recessed gate transistor is disposed in an active region of a semiconductor substrate. Two isolation regions disposed in the semiconductor substrate to define an active region therebetween. The recessed gate transistor includes a gate structure, a source doping region and a drain doping region. The gate structure has at least three fins forms a concave and convex bottom of the gate structure. The front fin is disposed in one of the two isolation regions, the middle fin is disposed in the active region and a last fin disposed in the other one of the two isolation regions. The front fin and the last fin are both cylindrical. A lower part of the gate structure is M-shaped when view from the source doping region to the drain doping region direction.

Dependencies are inferred from the claim text.