Fabricaion study of UV detectors using the opto-electrical and acoustic characteristics of III-nitride thin films

• Main Authors: Tzu-Chieh Chen, 陳子傑
• Other Authors: Hui-ling Kao
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/47687199427713093513

碩士 === 中原大學 === 電子工程研究所 === 95 === In this thesis, III-nitride materials, AlN and GaN, which uniquely present at the same time the excellent electronic, optoelectronic and acoustic properties, were employed to fabricate MSM photodetectors & SAW oscillators for UV detection. The dark current of Al/p-GaN MSM photodetector is 10.1pA at 20V, the photoresponsivity is 0.1A/W at 5V, the UV/visible ratio is approximately 2.5 orders, and minimum detectable power is probably 10nW. AlN MSM photodetectors were fabricated on AlN epitaxial thin film deposited on GaN/Sapphire using helicon sputtering system at the low temperature of 300°C. The dark current of the device is 670fA at 20V and photo current illuminated by D2 lamp is higher by one order. The characteristics of SAW devices on AlN/GaN/Sapphire and GaN/Sapphire and the characteristic frequency responded to the UV illumination were explored. Superior SAW properties in terms of insertion loss and sidelobe rejection have been obtained for the SAW devices made on AlN/GaN/Sapphire, compared to those of the ones made on GaN/sapphire. With the deposition AlN on GaN/Sapphire, it can help ease off the fabrication difficulties of SAW oscillators. The illumination effect on the SAW oscillators has been investigated. It showed a linear relationship between the radiation power and the frequency shift of oscillation for GaN/Sapphire and AlN/GaN/Sapphire SAW oscillators, indicating the feasibility for UV sensors. Finally, I have proposed a novel idea of UV detectors that combines the III–Nitrides SAW and MSM devices. The devices not only have the potential to measure optical power more accurately, but also have feasibility of tailoring the UV absorption edge of wavelength. The patent of this invention is pending now.