Method of manufacturing field effect transistors using sacrificial blocking layers

Abstract

Provided are a more stable semiconductor integrated circuit device and a method of manufacturing the same. The method includes providing a semiconductor substrate comprising a first transistor region having a stacked structure of a first gate insulating layer and a first gate and a second transistor region having a stacked structure of a second gate insulating layer and a second gate, forming a blocking layer in the first transistor region, conformally forming a second oxide layer on lateral surfaces of the second gate insulating layer and the second gate and on an exposed surface of the semiconductor substrate by performing oxidation in the second transistor region, removing the blocking layer of the first transistor region, forming a pre-spacer layer on the entire surface of the semiconductor substrate, forming a first spacer by anisotropically etching the pre-spacer layer of the first transistor region and forming a second spacer by anisotropically etching the second oxide layer and the pre-spacer layer of the second transistor region, and forming source/drain regions in the semiconductor substrate to complete a first transistor and a second transistor.