Semiconductor device with trench structure

摘要

A semiconductor device has a semiconductor substrate (30) with a trench (7) which has an insulating film (11) on its wall and which is filled with a conductive part (12). In one device, both the insulating film and the conductive part extending onto the substrate surface and, in a second device, the thickness of the insulating film section on the substrate surface is at least double that of the insulating film section on the trench wall. Both the insulating film and the conductive part may extend continuously into neighbouring trenches. Also claimed are processes for producing the above devices.