本論文中，我們採用表面處理來改善以鎳/金薄膜為蕭基接觸之氮化鎵金屬-半導體-金屬光檢測器的表現。
在用在表面處理的各種不同溶液中，經沸騰的氫氧化鉀酒精溶液處理的樣本可以有效除去負性氧化物薄膜及明顯降低表面能態。此外，內部增益可以經由550℃的氧氣回火處理來有效抑制。這此改善可歸功於p-type的氧化鎳的形成。在5伏偏壓下，製造在550℃回火過的經沸騰的氫氧化鉀酒精溶液表面處理過的樣本上的元件的光暗電流比可上升至1.078E4。
有時，在製造氮化鎵光電元上ICP乾性蝕刻是必要的。為了回復這些傷害，我們採用表面處理來改善元性特性。在表面處理過後，回火處理可以明顯地減少表面能態的數目及有效抑制缺陷促進的穿隧效應。在經過沸騰的氫氧化鉀酒精溶液表面處理過且回火過的元件，其光暗電流比大約在1.421E3。此外，氮化鎵金屬-絕緣體-半導體紫外光光檢測器也被製造。那個二氧化矽層是用PECVD的方法沉積的。我們發現元件特性可經由插入二氧化矽層而改善。對經ICP乾性蝕刻傷害過和經沸騰的氫氧化鉀酒精溶液表面處理過的樣本而言，光暗電流比可由改善6.92至16.88(MIS)。

In this thesis, we adopt the surface treatment to improve the performance of the GaN-based MSM photodetectors with thin Ni/Au film as Schottky contacts and investigated the characteristics of these devices.
Among the different kinds of solutions for surface treatment, the sample which has undergone boiled alcohol-based KOH surface treatment shows the most effect removal of thin native oxide and the much significant reduction of surface states. Besides, the internal gain effect can be efficiently suppressed by the anneal treatment under O2 ambient at 550℃. Such great improvement can be attributed to the formation of p-type NiO. It is also found that the rejection ratio (360/450nm) in response is up to 1.078E4 for 550℃ annealed MSM photodetector fabricated on the boiled alcohol-based KOH surface treated sample with a 5V applied bias.
Sometimes, it is necessary to fabricate these GaN-based optoelectronic devices with the inductively coupled plasma (ICP) dry etching method. In order to recover these damages, we adopt the method of surface treatment to improve the performances of the devices. After the surface treatment, the anneal treatment can more significantly decrease the numbers of surface states and the traps-assisted tunneling effect will be effectively suppressed, too. The rejection ratio is about 1.421E3 for the device annealed after boiled alcohol-based KOH surface treatment. Besides, the GaN-based MIS UV detectors are also fabricated. The SiO2 insulator was deposited by means of plasma enhanced chemical vapor deposition (PECVD). It is found that the devices performance have been improved by inserting the SiO2 layer. The rejection ratio (360/450nm MIS) can be improved from 6.92 to 16.88 for the sample ICP damaged and the sample treated by boiled alcohol-based KOH, respectively.

Reference

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