利用原子層沉積技術在不同溫度下製作氧化鋁/鍺金氧半元件之研究

Abstract

本論文以原子層沉積技術分別在150℃、200℃、250℃下成長七奈米的氧化鋁薄膜於N型鍺基板上，並使用熱蒸鍍機在樣品表面鍍上大約八十奈米的金屬鎳做為上電極，而樣品背面鍍上大約一百五十奈米的金-銻合金做為背電極，形成鎳/氧化鋁/鍺的金氧半元件。其中每個成長溫度下的樣品又分為沒有沉積後退火處裡其樣品其編號分別為Td150、Td200、Td250，與有沉積後退火處裡其樣品編號為PDA-Td150、PDA-Td200、PDA-Td250。樣品電性分析方面以高頻電容-電壓曲線與電流-電壓曲線，計算出等效電容厚度、等效介電系數、介面缺陷密度與漏電流密度。材料分析方面以X-射線繞射分析(XRD)確認氧化鋁之結晶向，遠紅外線傅立葉光譜分析(FTIR)研究每個樣品之化學鍵結之變化，X光光電子能譜儀(XPS)之縱深量測研究鍺、鋁、氧在氧化鋁薄膜中隨著不同厚度之化學含量分布。

關鍵字:原子層沉積技術、氧化鋁、鍺、金氧半元件

In this thesis, the 7 nm of Aluminum oxide Al2O3 was deposited on n-type Germanium wafer at 150℃, 200℃, and 250℃. Then 80 nm of Ni was deposited on Al2O3 as top electrode and 150 nm of Au-Sb is deposited on backside of Germanium wafer by thermal evaporator. Form a Metal-Oxide-Semiconductor device with structure of Ni/Al2O3/n-Germanium/AuSb. The as-deposited samples at different temperatures are noted as Td150, Td200, and Td250.The samples with post-deposition annealing treatment are noted as PDA-Td150, PDA-Td200, and PDA-Td250. In electronic analysis, the high frequency C-V and I-V curves is used to extract capacitance equivalent thickness (CET or EOT), effective k-value (keff), density of interface trap (Dit), density of leakage current (Jg). In material analysis, X-ray diffraction (XRD) is used to verify the crystalline of Al¬¬-2O3 thin film, Fourier transform infra-red spectrometry (FTIR) is used to investigate the chemical bond profile of samples, X-ray Photoemission Spectrometry Results (XPS) is used to investigate the chemical state of Ge 3d, Al 2p, and O 1s in Al2O3 ¬thin film with respect of depth.

KEYWARDS: Atomic Layer Deposition (ALD), Aluminum oxide (Al2O3), Germanium, MOS devise