TRENCH GATE SEMICONDUCTOR DEVICE AND METHOD OF MANUFACTURING THEREOF.

摘要

A trench-gate semiconductor device configuration is provided which is suitable for incorporation in integrated circuits, together with methods for its manufacture. A self-aligned drain region (12a) is provided below the device trench (18). The manufacturing methods include etching an initial trench into a semiconductor body (8), and annealing so as to cause migration of material such that a shallower trench with a cavity (36) below it are formed. The drain region is then formed in the cavity. A further cavity (52) may be used to form a buried isolation layer (56) below the drain region, e.g by thermal oxidation.