A Self-Aligned Metal Gate MOSFET Structure Utilizing The Oxidation Rate Variation on The Impurity Concentration

불순물 농도에 따른 산화막 성장률의 차이를 이용한 자기 정렬된 금속게이트 MOSFET 구조

A metal gate MOSFET with source/drain regions self-aligned to gate region is proposed. The proposed MOS transistor is fabricated by utilizing the higher oxidation rate of source/drain regions with high doping concentration when compared with channel region with moderate doping. The thick oxide on the source/drain regions reduces the gate and drain(source) overlap capacitance down to that of a self-aligned polysilicon gate device while allowing the use of a metal gate with much lower resistivity than the more commonly used polycrystalline silicon. A ring oscillator composed of 15 inverter stages has been computer simulated using SPICE. The results of the simulation show good agreement with experimental measurement confirming the fast switching speed of propesed MOSFET.