金屬閘極與絕緣層上鍺光偵測器

Metal Gate and Ge on Insulator Photodetector

李呈峻(Cheng-Jiun Lee)

指導教授 ： 劉致為

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.01361

摘要

本論文中，我們將作氮化鉭材料特性之研究，有關材料之功函數及其熱穩定性和金屬和介電質之接面將被探討。由於材料的功函數和晶格結構、結晶向以及應力有關。在實驗中發現，氮化鉭的功函數和熱穩定性之變化與製程中氮氣流量及熱退火溫度有直接關係。若製程中增加濺鍍機裡的氮氣流量，則所製作出來的氮化鉭之功函數會增加而其熱穩定性將會降低。
本論文之研究，利用快熱製程與氫離子佈植技術進行晶圓鍵結之方法。其中氫離子佈植技術是氫離子佈植到鍺晶圓至適當深度。然後使用結合晶圓鍵結技術將鍺晶圓與矽晶圓上有600奈米的硼磷酸玻璃絕緣層進行室溫黏合，黏合後之晶圓經由高溫處理，原植入之氫離子會受高溫影嚮而使所鍺晶圓在植入深度處分裂開，留下一層很薄的鍺。然而我們成功製作出”絕緣層上鍺”，同時用原子力顯微鏡發現鍺表面非常粗糙。利用爐管高溫下進行氫氣熱退火使絕緣層上鍺的表面粗糙度減少，由實驗結果看來氫氣熱退火有顯著且有效的降低絕緣層上鍺、矽的表面粗糙度。
最後，我們發現低溫熱退火更適合應用在絕緣層上鍺製程。經由低溫熱退火可以在絕緣層上鍺有很小的表面粗糙度。而鍺具有吸收紅外光的能力使它很有潛力成為高速光偵測器。本論文中，我們主要研究絕緣層上鍺—金氧半—光偵測器之特性。在這個結構中氧化層是用液相沉積法可以使照光產生的載子藉由多層缺陷的幫助而穿過氧化層，同時應用金屬閘極技術來減少暗電流。在實驗中，絕緣層上鍺—金氧半—光偵測器具有高效率和高光響應，同時可工作在850，1300和1550 奈米的光波長，很適合運用於光纖通訊上。

關鍵字

金屬閘極 ； 絕緣層上鍺 ； 光偵測器 ； 氮化鉭 ； 晶圓鍵結技術

並列摘要

In this thesis, the material properties of tantalum nitride (TaN) gate have been studied, such as proper work-function, thermal stability of the gate itself and also in contact with the dielectric underneath. Because the work function of a material depends on its crystalline structure, orientation, and composition. In our experiment, the work-function (Wm) variation and thermal stability of TaN are discussed as a function of nitrogen partial-flow rates and annealing temperature. The nitrogen partial-flow rates are increased in reactive sputtering, thus the thermal stability of TaN is decreased and work-function is increased.
Then the directly hydrophilic wafer bonding method is achieved by rapid thermal process and smart-cut process. Implanting hydrogen ions into the germanium wafer to from an in-depth weaken layer. The germanium (Ge) wafer is successfully bonded to silicon (Si) wafer capped with 600nm BPSG by the wafer bonding technology, thus thermal treatments and layer transfer taking place along the in–depth weaken layer (thin film Ge). The Ge-on-insulator (GOI) structure accomplished, and the thin film Ge surface observed very rough by atomic force microscopy (AFM). The GOI surface roughness is reduced by thermal rapid annealing with hydrogen gas in furnace, and hydrogen annealing is obvious and promising to reduce SOI and GOI surface roughness.
Finally, GOI fabrication is more suitability for low temperature splitting annealing. The low surface roughness is achieved by low temperature splitting annealing on thin film Ge. Since the ability of germanium to absorb in the near infrared makes it an interesting candidate for high-speed photodetector applications. Thus, the GOI MOS photodetectors are studied in this thesis. The leakage current at inversion bias is reduced by metal gate technique, and the oxide of GOI MOS photodetectors is deposited by liquid phase deposition (LPD) that carriers can tunnel through oxide via the assistance of multiple traps. In experiment, the novel GOI PMOS photodetectors have high responsivity and high quantum efficiency at 850nm. Therefore, the GOI photodetector can operate with 850nm, 1.3μm and 1.5μm lightwave and can be applied to the fiber optic communications.

並列關鍵字

Metal Gate ； Ge on Insulator(GOI) ； Photodetector ； smart cut ； tantalum nitride(TaN) ； work-function ； thermal stability

參考文獻

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