METHOD FOR FABRICATING THE SAME OF SEMICONDUCTOR DEVICE WITH BULB RECESS GATE

摘要

A method for fabricating a semiconductor device having a bulb recess gate is provided to increase the channel length of a recess gate and reduce an ion implantation doping density by guaranteeing uniformity of forming a bulb in a recess pattern. A semiconductor substrate(31) is selectively etched to form a first recess(34). A spacer(35) is formed on the sidewall of the first recess, made of an oxide layer. Predetermined bottom power is applied to isotropically etch the semiconductor substrate under the first recess so that a second recess(36) wider and more rounded than the first recess is formed. The first and second recesses can be formed by an in-situ method in the same chamber. A gate pattern is formed which is partially buried in a recess composed of the first and second recesses and partially protrudes from the semiconductor substrate.