Method for manufacturing mos transistor of semiconductor device

Abstract

Disclosed is a method for manufacturing a semiconductor device including a low-voltage MOS transistor and a high-voltage MOS transistor. The present method includes a low-voltage well implantation process on a semiconductor substrate to form a first well in a first region of the substrate and a second well in a second region of the substrate; forming first and second gate oxide layers and first and second gate electrodes in the first and second regions, respectively; forming a first photoresist pattern to expose the first region; forming a first LDD region in the first region exposed by the first photoresist pattern and the first gate electrode; removing the first photoresist pattern; forming a second photoresist pattern to expose the second region; forming a second LDD region in the second region exposed by the second photoresist pattern and the second gate electrode; performing a compensational implantation on the second region to adjust a well concentration for the high-voltage MOS transistor; and removing the second photoresist pattern.