本文利用射頻磁控濺鍍法沉積氧化鎵鋅薄膜，討論在不同製程條件下薄膜的特性，並將這些薄膜作為主動層應用於紫外光檢測器及薄膜電晶體，進行分析與討論其特性。
首先以磁控濺鍍法在不同的製程條件下沉積氧化鎵鋅薄膜，並從三方向去討論氧化鎵鋅薄膜特性，分別是薄膜結構特性、薄膜光學特性及薄膜表面和縱深分析。在結構特性上，氧化鎵鋅薄膜表面緻密且隨溫度上升有晶相產生。而在光學特性的部分，由於鎵的能隙極大，有鎵成份存在於薄膜，使得氧化鎵鋅薄膜成為一種寬能隙的材料，主要吸收紫外光波段，並且其於實驗顯示薄膜在可見光區有80%的穿透率，可知氧化鎵鋅薄膜是一種寬能隙且高穿透的材料。此外，從X射線光電子能譜（XPS）圖得知，薄膜之中的氧空缺會由於製程中氧氣通入量有所變動而有最佳參數。
實驗的第二部分是將氧化鎵鋅應用於光檢測器，改變退火的溫度和濺鍍通氧流量，比較其特性差異。當退火溫度提高和適當的通氧流量時，能有效的抑制暗電流。在退火五百度及氧氣流量比例為1%的情況下，元件的暗電流為1.54 × 10-11安培，亮暗電流比為1.12 × 107，響應拒斥比為5.44×105。
實驗的第三部分是使用二氧化矽做為氧化鎵鋅薄膜電晶體的閘極介電層，並且藉由濺鍍通氧流量以及退火環境的改變，來找出薄膜電晶體最佳參數。在濺鍍氧氣流量比例為8%及氧氣退火三百度一小時的情況下，得到場效電子遷移率為0.93 cm2/V∙s，臨界電壓為0.67 V，次臨界擺幅為0.8 V/dec，ON/OFF電流比為105。本文也將薄膜電晶體延伸應用為光電晶體，在偏壓-5V的情況下可得到響應拒斥比為6.28×105。此外，我們把氧化鎵鋅薄膜電晶體的鋁電極替換成氧化銦錫電極，做成全透明的薄膜電晶體。

In this thesis, gallium zinc oxide (GaZnO) is deposited by RF magnetron sputtering and the films’ properties are discussed thoroughly under different processing ambiences. Next, we will apply GaZnO thin films in photodetectors, thin film transistors and phototransistors. The properties of the devices are discussed in detail.
First, we utilize the RF-sputtering system to grow thin-films with different conditions and the films’ properties are research into three aspects which are structural, optical, and surface/depth element analysis. Thin films are amorphous as-deposited and the crystalline phase gradually appears with the increasing of annealing temperatures. For the optical analysis, owing to the large bandgap of gallium, GaZnO thin films could be used as wide bandgap material, absorbing ultraviolet light. Furthermore, the transmittance can achieve more than 80% in the visible region. The XPS shows that the oxygen vacancies will be affect by the oxygen flow ratio. For surface/depth element analysis, we can observe the smooth surface of the films through AFM measurement. The smooth surface of the films leads to lower surface density of states, which is beneficial for the performance of the devices.
In the second part of the experiment, GaZnO photodetectors were fabricated by radio frequency magnetron sputtering on quartz substrates. The films’ Ga content were relatively high to enlarge the bandgap and obtain low dark current. In addition, it was found that the devices’ performance was significantly improved by proper gas flow ratios of O2/Ar during deposition and post-annealing temperature. With oxygen ratio 1% annealed at 500 for one hour, the on-off current ratio of sample was ~107, the responsivity reached 16.08 A/W and the UV-to-visible rejection ratio was 5.44×105.
In the third part, GaZnO TFTs are realized. Manipulation of oxygen flow ratios is conducted to find the optimized TFTs. The best features would be presented as the sputtering oxygen flow rate controlled at 8% to properly compensate the oxygen vacancies. Compared with post-annealed in air, annealing in O2 showed better characteristics. With the optimized conditions, the transistor could exhibit an on-off ratio of five orders of magnitude, mobility of 0.93 cm2/V∙s and SS of 0.8 V/dec. Our results broaden the applicability of GaZnO TFTs to photodetectors. When a negative gate bias was applied, the optimized GaZnO phototransistor exhibited fine photo properties. With an UV light wavelength of 280 nm and an applied gate bias of -5 V, the measured responsivity of the device was 0.84 A/W, and the UV-to-visible rejection ratio was 6.28×105. The results indicate that the fabricated device is suitable for solar-blind photodetectors. In addition, we fabricated fully transparent thin film phototransistor by replacing aluminum electrode with ITO electrode and its UV-to-visible rejection ratio was 1.7×103.

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