氮化鎵金屬-半導體-金屬光偵測器之研究

Abstract

在本論文中我們針對氮化鎵金屬-半導體-金屬光偵測器作廣泛地研究，所製造出的光偵測器元件，在施加偏壓10伏特時，得到的暗電流密度為1.5 A/cm2，而其截止波長為 365 nm。元件的響應度在截止波長以下和可見光部分相差大於3個數量級，而當入射光波長為350 nm時，得到的響應度為1.66 A/W。另外也探討了使用不同金屬包括鎳/金、鉑/金、鈀/金作為光偵測器的金屬電極，對所製作之金屬-半導體-金屬光偵測器特性之影響，並觀察這些元件在長時間高溫（400 ~600 ）持續熱退火後，光偵測器暗電流和響應度的變化。經長時間持續熱退火至600 後，鎳/金蕭基接觸之金屬-半導體-金屬光偵測器在暗電流展現出較佳的穩定性，鉑/金、鈀/金蕭基接觸之金屬-半導體-金屬光偵測器則展現出較大的增益。另外也觀察了截光器頻率對光偵測器響應度的影響。

In this thesis, GaN metal-semiconductor-metal photodetectors have been studied extensively, including the fabrication and characterization of the photodetectors, the annealing effects on different metal electrodes, and the frequency-dependent photoresponse. The fabricated MSM photodetector have a very low dark current density, 1.5 A/cm2, at 10V bias. The responsivity is 1.66 A/W at a wavelength of 350nm. Over three orders of magnitude difference between UV and visible region have been achieved. After high temperature annealing, from 400 to 600 , the MSM photodetectors with Ni/Au electrodes were more stable in dark current than those with Pt/Au and Pd/Au electrodes, and the later have a larger photoresponse gain.