Single crystal u-mos gates using microwave crystal regrowth

Abstract

Semiconductor devices and methods for making such devices are described. The UMOS semiconductor devices contain single-crystal gates that have been re-grown or formed at low temperature using microwaves. The devices can be formed by providing a semiconductor substrate, forming a trench in the substrate, forming an insulating layer in the trench, depositing a pre-gate layer on the insulating layer, the pre-gate layer comprising a conductive and/or semiconductive material (Si or SiGe) with a non-single crystal structure, contacting the pre-gate layer with a seed layer with a single-crystal structure, and heating the pre-gate layer using microwaves at low temperatures to recrystallize the non-single crystal structure into a single-crystal structure. These processes can improve the resistance and mobility of the gate either as a single crystal structure, optionally with a silicide contact above the source-well junction, enabling a higher switching speed UMOS device. Other embodiments are described.