- 學位論文
用ALD技術提升量子點紅外光偵測器操作溫度之研究
Passivation of Quantum Dot Infrared Photodetector with Al2O3 Deposited by Atomic Layer Deposition
摘要
本文的研究目的在於提升量子點紅外光偵測器的操作溫度，主要是利用原子層沉積技術將氧化鋁鍍在元件表面，來達到修補元件表面因濕蝕刻造成的缺陷以及壞鍵，進而降低元件的暗電流並直接提高量子點紅外光偵測器的操作溫度。 本文在第一個實驗裡發現了用原子層沉積技術在元件表面鍍完氧化鋁後，要經過快速高溫熱退火處理才能將元件表面的缺陷順利修補，達到修補表面及降低暗電流的能力。本文在第二的實驗裡證實了鍍氧化鋁時溫度越高，鍍膜品質更好，可以使元件暗電流下降更多；此外，提升鍍完氧化鋁後快速高溫熱退火的溫度也能達到更好的修補元件表面缺陷的能力，而使元件暗電流降低，提升操作溫度。 本文第三個實驗中探討了鍍氧化鋁提升操作溫度的機制和氧化鋁厚度之間的關係，間接證實了此降低暗電流現象只與元件和氧化鋁界面有關，在本文的最後也嘗試出目前最佳的鍍膜條件及高溫熱退火參數，最終可有效將元件操作溫度提升凱氏溫度四十度。
並列摘要
The purpose of this thesis is to promote the operation temperature of QDIPs. It is believed that the surface passivation by ALD can fix the surface defect such as dangling bond generated by the wet etching process (mesa formation). By this way, the dark current can be reduced and the operation temperature of QDIPs can be raised. In the first experiment of this thesis, it is found that after coating the Al2O3 layer surrounding the device. The As2O3, the interface oxide, will pin the Fermi-level which will cause the large leakage current of the device. It could be removed by higher temperature annealing which can ensure the effective surface passivation. In the second experiment of this thesis, it is proved that the higher growth temperature of Al2O3 layer which can ensure the better quality of Al2O3 layer and higher RTA temperature make the surface passivition more effective which leads to lower dark current In the third experiment of this thesis, the Al2O3 layer thickness effect is discussed. It is proved that the mechanism of reducing dark current only associated with interface effect. Finally, the best recipes for surface passivation on QDIPs is revealed. The operation temperature of the QDIP can be raised over 40 K and operated at 130 K.