Effect of poly silicon thickness on the formation of Ni-FUSI gate by using atomic layer deposited nickel film

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• 作者：Jong-Bong Ha ; Sang-Won Yun ; Jung-Hee Lee
• 关键词：Metal gate ; Nickel silicide phase ; Atomic layer deposition ; Fully silicidation ; Flatband voltage
• 刊名：Current Applied Physics
• 出版年：2010
• 出版时间：January 2010
• 年：2010
• 卷：10
• 期：1
• 页码：41-46
• 全文大小：734 K

文摘

The effect of poly-Si thickness on silicidation of Ni film was investigated by using X-ray diffraction, auger electron spectroscopy, cross-sectional scanning transmission electron microscopy, resistivity, I–V, and C–V measurements. The poly-Si films with various thickness of 30–200 nm were deposited by LPCVD on thermally grown 50 nm thick SiO₂, followed by deposition of Ni film right after removing the native oxide. The Ni film was prepared by using atomic layer deposition with a N²-hydroxyhexafluoroisopropyl-N¹ (Bis-Ni) precursor. Rapid thermal process was then applied for a formation of fully silicide (FUSI) gate at temperature of 500 °C in N₂ ambient during 30 s. The resultant phase of Ni-silicide was strongly dependent on the thickness of poly-Si layer, continuously changing its phase from Ni-rich (Ni₃Si₂) to Si-rich (NiSi₂) with increasing the thickness of the poly-Si layer, which is believed to be responsible for the observed flat band voltage shift, ΔV_FB, in C–V curves.