在本論文中，吾人主要著重在氧化鎵系列半導體之研製，利用射頻磁控濺鍍的方式沉積以氧化鎵為主要材料的薄膜，並搭配熱退火去改善光檢測器特性。實驗分為三個部分，首先，我們成功製作了以鈦/鋁為電極的氧化鎵光檢測器，在氧氣退火處理後，在高溫下(例：1000℃)可以達到較好的單斜氧化鎵品質。在250nm光照與10V偏壓之下，氧化鎵的截止波長變得較為明顯，元件的部分光特性在退火處理後可以有效改善，這樣的結果說明使用氧化鎵組裝成solar-blind紫外光光檢測器的實用性。
接著，我們藉由共濺鍍(co-sputter)的方式，在氧化鎵薄膜中參雜不同的半導體化合物，例如參雜氧化銦，可以適當的調整光檢測器的截止波長，例如在較高的銦含量時，截止波長會往長波長位移的現象，並增強光響應。除此之外，我們進一步將元件回火至800oC，其紫外光對可見光的拒斥比可到達五個數量級，進一步證明透過簡易的共濺鍍和熱回火，可以做出品質良好的光檢測器。
最後，我們將氧化銦鎵用來作為薄膜電晶體(TFT)的通道層，探討不同比例的銦含量，對薄膜電晶體電性的影響，我們發現，隨著銦含量的增加，通道的導電率會增加，且元件的臨界電壓(Vth)會往負值移動，隨後照光，我們發現藉由調變不同的光波長，可控制電晶體的開關，說明氧化銦鎵可進一步應用為光電晶體。

The main goal of this dissertation is the fabrication and analysis of Ga2O3-based ultraviolet (UV) sensor devices. The Ga2O3 thin film was grown on sapphire substrate by Radio-Frequency Magnetron Sputter technique with thermal annealing treatment to improve the characteristics of the devices. The experiment is divided into three parts：
First, the Ga2O3 PDs with Ti/Al electrodes are successful fabricated. After the O2 annealing process, the device characters will be effectively improved. The β-Ga2O3 monoclinic phase and better crystalline quality were observed at higher annealing temperature. With an incident light of 250nm and 10V applied bias, the cut-off become sharper. The Ga2O3 PD after O2 annealing treatment at 800oC has the advantages such as low dark current 1.16 × 10-11 (A) and large deep-UV-to-visible rejection ratio. Such a result indicates that it is useful for design of β-Ga2O3 solar-blind UV detectors.
Second, we describe the preparation of (Ga1_xInx)2O3 films on sapphire substrates by rf magnetron co-sputtering using two ceramic targets of Ga2O3 and In2O3 and post-annealed at various temperature. With the increasing indium content, the threshold wavelength could be adjusted to the longer wavelength. Besides, the device characters will be better after O2 annealing treatment. It was also found that fabricated PD exhibits extremely large deep-UV-to-visible rejection ratio at the optimized condition which In2O3 power was fixed at 25W and post-annealed to 800°C.
Finally, we used (Ga1_xInx)2O3 films as the channel of thin film transistor and further fabricate the bottom-gate deep-UV sensitive phototransistor. We will discuss the influence of electrical properties due to different indium content. It was found that the conductance increased and the threshold voltage was shift to negative voltage while increasing the indium content. Moreover, there is a significant 100 times increase in the drain current of Ga2O3 TFT upon UV light illumination. We can modulate the light wavelength to control the switching of the transistors. It is concluded that indium gallium oxide TFT can be further used as a promising light photo-detecting device for phototransistor applications.

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