矽化鈦/鈦矽硼雙合金層的形成與其應用

Abstract

本論文研究矽化鈦/鈦矽硼雙合金層的形成與其應用.首先利用超高真空化 學氣相沉積系統沉積一層矽硼層在複晶矽上當作p+/n 淺接面的擴散源.再 蒸鍍一層鈦於表面,以爐管加熱回火使之形成矽化物.從Auger & TEM 的分 析,在氮氣中經過630度C-20分鐘的回火處理發現矽化鈦/鈦矽硼雙合金層 的形成.經由ESCA証實鈦-矽-硼由矽化鈦及硼化鈦所組成.SEM顯示上層矽 化鈦的微結構與傳統的複晶矽化鈦不同.又由TEM 的橫截面圖顯示矽化物/ 矽的介面比傳統的複相矽化鈦平坦,且有較好的熱穩定度來防止聚集發生. 電性方面,經過900度C-20分鐘的退火,可得到一個0.12 um 的淺接面.鍍上 一層30 nm 厚的鈦,在700度C到900度C-20分鐘的回火矽化範圍內,其逆向 電流密度大約2nA/cm*cm,順向理想參數趨於1.此二極體不僅在低熱能的回 火條件下能有好的電性表現,在高溫的製程中也有較優良的熱穩定性防止 電性劣化. In this thesis, we present the formation of Ti-Si/Ti-Si-B bilayer and its applications. The Si-B layer, as a diffusion source to form shallow junction, was deposited on poly- crystalline silicon films by UHV/CVD system. The Ti of 30 nm in thickness is evaported subsequently to reacted with Si-B layer. From the Auger profiles, the formation of Ti-Si/Ti-Si-B bilayer after 630℃ sintering for 20 min in an N2 ambient was found. From the analysis of ESCA, the Ti-Si-B is composed with TiSi2 and TiB2. The microstructure of the top Ti-silicide is different from conventional polycide as investigated by SEM. From the TEM micrographs, the interface of silicide/Si is more uniform than that of conventional polycide, and the silicide has better thermal stability to resist agglomeration. The p+/n junction depth is about 0.12um after 900℃ drive-in for 20 min in an N2 ambient. Reverse junction current density about 2nA/cm *cm and the ideality factor approach to 1 were obtained after silicidation at 700-900℃ for 20 min, respectively. Better electrical performance after low thermal budget process and better thermal stability were achieved.