III族氮化物之金屬-半導體-金屬紫外光感測器之特性研究

Characterization study of III-nitride based metal-semiconductor-metal UV detectors

張欣會(Shin-Hui Chang)

指導教授 ： 高慧玲

中原大學/工學院/電子工程研究所/碩士(2008年)

https://doi.org/10.6840/cycu200800238

摘要

本論文利用三族氮化物中具有良好光電特性之氮化鎵及氮化鋁材料研製平面式金屬-半導體-金屬結構紫外光偵測器，並探討其特性。
在氮化鎵金屬-半導體-金屬光偵測器中，將GaN/Sapphire基板經過稀鹽酸表面處理，放入迴旋濺鍍系統濺鍍金屬鋁作為指叉電極，算出元件金半接面之理想因子n為1.0147，蕭特基障礙高度ψB為0.794 eV，在偏壓20 V時，暗電流為100 pA。並針對指寬指隙設計，提升元件效能，入射光強度為1.99mW時，在偏壓10V可得到響應度0.0113 A/W，與目前文獻上最好的p-GaN MSM元件響應度相比，同樣有著很好的響應度，且元件之光電流與入射光功率呈現很好的線性度，證明所製作之氮化鎵MSM 元件非常適合當紫外光偵測器。
氮化鋁金屬-半導體-金屬光偵測器則是用In situ metallization製程，利用低溫迴旋濺鍍法在氮化鎵/藍寶石基板上沉積之氮化鋁，再直接濺鍍金屬鋁作為指叉電極，比較目前文獻製作出來的氮化鋁MSM元件，可得到很好的元件金半接面之理想因子1.0125，算出蕭特基能障高度為0.916eV，並有很低的暗電流為1.39 pA，提升了元件的特性，使用150 W氘燈入射，光暗電流差距可到兩個order，且元件之光電流與入射光功率呈線性，顯示所製作之氮化鋁MSM元件，很適合針對深紫外光波段偵測。

關鍵字

氮化鎵 ； 紫外光感測器 ； 金屬-半導體-金屬光偵測器 ； 氮化鋁 ； 迴旋濺鍍系統

並列摘要

In this thesis, III-nitride materials, GaN and AlN, which uniquely present at the same time, the excellent electronic and optoelectronic properties, were employed to fabricate the metal-semiconductor-metal (MSM) photodetectors for UV detection.
The native oxide on GaN surface was removed by HCl before the metallization of Al electrodes for MSM devices. The dark current of the GaN MSM photodetector is 100pA at 20V. The ideal factor and Schottky barrier height derived from the dark current are 1.0147 and 0.794eV, respectively. The finger width and space of the interdigital electrodes were varied in order to improve the device performance. The responsivity of the p-type GaN MSM device is 0.0113A/W at 10V when illuminated by He-Cd laser with the power of 1.99mW. It is as good as that of the p-type GaN MSM in the literature. In addition, the photo current increases linearly with the illuminating power, indicating that the GaN MSM devices are suitable for UV light detection.
AlN MSM devices were fabricated on AlN epitaxial thin film deposited on GaN/Sapphire substrates using helicon sputtering system at the low temperature of 300°C. The device characteristic was found to be improved by in situ metallization of Al electrodes. The extremely low dark current (1.39pA at 20V), the ideal factor (1.0125) and the Schottky barrier height (0.916eV) are superior compared to those of AlN MSM in the literature. When the device was illuminated by the 150W D2 lamp, the ratio of the induced photocurrent to dark current is more than 2 orders of magnitude. The illumination effect also shows the linear relationship between the radiation power and the photo current for the MSM devices, indicating the potential applicability for deep UV sensors.

並列關鍵字

AlN ； Ultraviolet sensor ； Helicon sputtering system ； GaN ； MSM photodetector

參考文獻

1.E Monroy, E Mu˜noz, F J S