Patent ID: 8835261
Filing Date: 2014-09-16
Classification: H01L

Abstract:
1. A method for forming a metal-oxide-semiconductor field effect transistor (MOSFET) structure, the method comprising: providing a semiconductor substrate; forming a patterned masking layer on the semiconductor substrate; etching a semiconductor layer of the semiconductor substrate to form at least one semiconductor body; removing the patterned masking layer; depositing an oxidation blocking material around and in direct contact with the at least one semiconductor body; etching back the oxidation blocking material to expose an upper portion of the at least one semiconductor body; oxidizing the upper portion of the at least one semiconductor body so as to form a dielectric cap having a match stick head shaped cross section over the remaining portion of the at least one semiconductor body, wherein the match stick head shaped cross section includes a combination of the at least one semiconductor body and the dielectric cap, wherein the match stick shaped head cross section is wider at a portion distal from the semiconductor substrate than a portion proximal to the semiconductor substrate, and wherein a material of the semiconductor cap tapers along the at least one semiconductor body from a portion of the at least one semiconductor body distal to the semiconductor substrate to a portion of the at least one semiconductor body proximal to the semiconductor substrate, wherein a width of the remaining portion of the at least one semiconductor body is less than a width of the dielectric cap; removing the oxidation blocking material; forming a gate dielectric layer on the remaining portion of the at least one semiconductor body and the dielectric cap; and forming at least one electrically conducting gate on the gate dielectric layer, wherein the gate dielectric layer is on the remaining portion of the at least one semiconductor body and the dielectric cap, and wherein the width of the remaining portion of the at least one semiconductor body is less than a width of the dielectric cap.