氧化鋁鈍化層對金屬絕緣層半導體穿隧二極體的影響與其在感光應用之研究

Abstract

本篇論文探討了氧化鋁鈍化層對於金屬絕緣層半導體(MIS)穿隧二極體的電性表現的影響，此元件的結構為在MIS穿隧二極體外圍成長上氧化鋁層作為鈍化層，我們發現到這樣的元件有著對於周圍少數載子變化十分敏感的特性，因此將其應用於感光上。在第二章中，我們對於其電容對電壓與電流對電壓兩種電性行為進行量測，發現到氧化鋁鈍化層會使得一般MIS穿隧二極體的深空乏行為被抑制，並且在相同氧化層厚度的情況下其在反轉區可以得到較大的電流，我們認為這樣的行為源自於鈍化層會強化元件周邊電場，使得在氧化層的壓降提升，穿隧電流因此增加。第三章中我們則對於此元件在感光上的表現進行探討，發現此元件因為外圍電場的增強可以對於周邊載子的變化變得更為敏感，無論是在電容、電流在不同光強度下相較於單純的對照組穿隧二極體有更明顯的反應，因此我們透過氧化鋁鈍化層可以進一步提升MIS穿隧二極體元件對於光偵測的敏感度，使其成為一個更好的感光元件選擇。

In the thesis, the influence of aluminum oxide passivation (AOP) layer on the electrical characteristics of metal-insulator-semiconductor tunnel diodes (MISTD) is investigated. The structure of this device contains an AOP layer surrounding MISTD. It is observed that AOP-MIS device is sensitive to the minority carrier change, and therefore we propose to use it as a light sensor. In Chapter 2, the capacitance versus gate voltage and current versus gate voltage are measured. It was found that the deep depletion behavior happening in MISTD device would be suppressed. Furthermore, larger current in inversion region is also observed in AOP-MIS device. We consider the reason of this behavior is originated from the enhancement of fringing field caused by AOP layer. Therefore, the voltage drop on the oxide layer becomes larger and leads to increase of tunneling current. In Chapter 3, light sensing performance of this device is studied and discussed. It is found that due to the larger fringing field, the sensitivity of the variation of extra carriers is increased. The differences of both capacitance and current show more obvious change than MISTD under light and dark condition. Consequently, it is considered that we can further increase the light sensitivity of MISTD with the help of AOP layer, and make it a better choice of light sensing.