METHOD FOR FABRICATING DUAL GATE OXIDE LAYER OF SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for fabricating a dual gate oxide layer of a semiconductor device is provided to prevent a gate oxide layer from being weakened by forming a middle temperature oxide layer as a buffer layer on gate oxide layers having different thicknesses. CONSTITUTION: A gate formation oxide layer(120) is formed on an isolation region(110) and an active region in a semiconductor substrate(100). A buffer layer(160) is formed on the gate formation oxide layer. A photoresist pattern(130) is formed on the buffer layer to expose the buffer layer on the active region in a portion for the second gate oxide layer. A part of the buffer layer and gate formation oxide layer existing on the active region in the portion for the second gate oxide layer is selectively etched to expose the active region in a portion of the second gate oxide layer by using the photoresist pattern as an etch mask. The photoresist pattern is eliminated while the residual buffer layer protects the residual gate formation oxide layer. The buffer layer is removed. A process for forming a thermal oxide layer is performed to form an oxide layer on the active region in the portion for the gate formation oxide layer, the isolation region and the second gate oxide layer so that the first and second gate oxide layers are formed.