具平面式與嵌入式電極的氮化鎵金屬-半導體-金屬光偵測器之製作與光電特性量測

Abstract

我們在無參雜的氮化鎵(GaN)基板上製作出柵狀結構之紫外光金屬-半導體-金屬(MSM)光偵測器。我們設計了不同電極寬度及電極間距組合的MSM光偵測器，用以探討分析各種暗電流、光電流傳導機制及光響應頻譜。 在製程上，我們以白金為電極材料，分別製作出平面式電極與嵌入式電極的MSM光偵測器。在元件特性量測上，我們分別量測了元件的暗電流、光電流與光響應頻譜。我們發現在平面式電極的MSM之暗電流主要由表面漏電流所主導，而嵌入式電極的MSM之暗電流主要由內部漏電流所主導。製作出的氮化鎵MSM光偵測器的光響應範圍在310 ~ 370 nm之間。嵌入式電極的MSM光偵測器對波長為360 nm的光有最大響應度為0.019 A/W，而平面式電極的MSM光偵測器在360 nm處有最大響應度為0.009 A/W。

We fabricated ultraviolet metal-semiconductor-metal (MSM) photodetectors by depositing interdigitated Pt metal film onto planar and recessed undoped-GaN wafers. Various metal electrode structures and semiconductor surface processing were used to investigate the conduction mechanism of dark currents and photocurrents of GaN MSM photodetectors. We characterized the current-voltage relationships and spectrum responsivities of MSM photodetectors. We found that dark current is dominated by the surface leakage current for the planar MSM detectors and is dominated by the internal leakage current for the recessed-electrode MSM detectors. The photosensitive spectrum range is between 310 nm and 370 nm. For these GaN MSM detectors The peak responsivity of the planar MSM detectors is 0.009 A/W at 360 nm, while the peak responsivity of the recessed-electrode MSM detectors is 0.019 A/W at 360nm.