METHOD FOR FORMING DUAL GATE OXIDE LAYER

摘要

PURPOSE: A method for forming a dual gate oxide layer is provided to be capable of improving the reliability of the dual gate oxide layer by implanting lightly doped dopants for increasing and decreasing oxidation speed. CONSTITUTION: A sacrificial layer(23) is formed on a semiconductor substrate(21). The first ion implanted layer(25) is formed on one lower portion of the sacrificial layer by implanting the first lightly doped ions for decreasing oxidation speed. The second ion implanted layer(27) is formed on the other lower portion of the sacrificial layer by implanting the second lightly doped ions for increasing oxidation speed. After removing the sacrificial layer, the thick and thin gate oxide layer are simultaneously formed on the semiconductor substrate.