選擇性鎢化學沈積法中氟對閘極氧化層的影響

Abstract

在本篇論文中,我們研究了氟對閘極氧化層的影響.鎢化學沈積法中的 氟會擴散進入閘極氧 化層並對崩潰電荷產生極大的影響,特別是接受高溫 的回火處理後.我們亦觀察到該崩潰電荷 的減少在閘極氧化層的厚度變薄 時更為顯著.大量的氟會便固定氧化層電荷及介面陷阱電荷 密度增加.被 氟取代而未鍵結的氧形成固定氧化層電荷及在電子注入過程中形同電洞陷 阱,尤 其在高溫的回火處理者. The effects of fluorine on gate dielectric reliability were studied.Fluorine was introduced by W-CVD into gate oxide as indicated by SIMS measurements.A large detrimental effect on the Qbd value of the MOS capacitors at high annealing temperature especially for the capacitor with thinner gate oxide thickness was observed. Excess amount of fluorine incorporation enhances the generation of fixed charge and interface trap density. Nonbridging oxygen centers act as fixed charges, and hole trap during F-N hot electron injectionA trappy fluorine-enriched oxide is obtained at high annealing temperature.