Patent ID: 8980716
Filing Date: 2015-03-17
Classification: H01L

Abstract:
1. A method for fabricating a semiconductor device, comprising: forming a sacrificial structure having gaps on a semiconductor substrate; forming one or more spacers at sidewalls at said gaps of the sacrificial structure, wherein the one or more spacers are entirely formed above a topmost surface of the semiconductor substrate; forming trenches into the semiconductor substrate between the spacers; forming gate electrodes in the trenches that are insulated from the semiconductor substrate by gate insulator, wherein tops of the gate electrodes are recessed from a surface of the semiconductor substrate; filling remaining portions of the trenches with thick insulator to at least a top of the sacrificial structure, wherein the one or more spacers are not removed before the thick insulator is formed; removing the sacrificial structure leaving the thick insulator on top of the gate electrodes; and forming contacts to the substrate in the area formerly covered by the sacrificial structure whereby the contacts are self-aligned to the gate trenches by the thick insulator covering the tops of the gate electrodes.