Patent ID: 7235449

Claim:
A method of forming a gate oxide film for a high voltage region of a semiconductor device, comprising: forming patterns on a semiconductor substrate having a high voltage region, thereby exposing only a gate oxide film formation region for the high voltage region; forming an aluminum oxide (Al 2 O 3 ) metal oxidization layer on the entire surface including the patterns, wherein the aluminum oxide metal oxidization layer is formed through the following steps (a) to (d): (a) supplying an aluminum source; (b) carrying out a first purification step; (c) supplying an oxygen reaction gas to form an Al 2 O 3 reaction product; and, (d) purifying the Al 2 O 3 reaction product in a second purification step, wherein steps (a)–(d) form one cycle, and performing a process of removing the patterns, thereby leaving the aluminum oxide metal oxidization layer only in the gate oxide film formation region for the high voltage region.