切割角蓝宝石基氧化镓薄膜MOCVD外延及日盲紫外光电探测器制备

Substrates and Fabrication of Solar-Blind Ultraviolet Photodetector

本文使用金属有机物化学气相沉积(MOCVD)法在不同切割角的c面蓝宝石衬底上外延氧化镓(β-Ga_(2)O_(3))单晶薄膜,揭示了衬底切割角对外延薄膜晶体质量的影响规律。研究表明,当衬底切割角为6°时,β-Ga_(2)O_(3)外延膜具有较小的X射线摇摆曲线半峰全宽(1.10°)和最小的表面粗糙度(7.7 nm)。在此基础上,采用光刻、显影、电子束蒸发及剥离工艺制备了金属-半导体-金属结构的日盲紫外光电探测器,器件的光暗电流比为6.2×10^(6),248 nm处的峰值响应度为87.12 A/W,比探测率为3.5×10^(15) Jones,带外抑制比为2.36×10^(4),响应时间为226.2μs。

In this work,single-crystal gallium oxide(β-Ga_(2)O_(3))thin films were epitaxially grown on different off-cut angled c-plane sapphire substrates by metal organic chemical vapor deposition(MOCVD),and the effect of off-cut angles on the crystal quality and surface roughness of the epitaxial films were investigated.For theβ-Ga_(2)O_(3) epilayer grown on the 6°off-cut angled sapphire substrate,the full width at half maximum(FWHM)of the rocking curve is reduced to be 1.10°,together with the smallest surface roughness of 7.7 nm.Consequently,the metal-semiconductor-metal structured solar-blind ultraviolet photodetectors were fabricated by lithography,development,electron beam evaporation and lift-off techniques.The photodetector has excellent performances,including photo-dark current ratio of 6.2×10^(6),peak photoresponsivity of 87.12 A/W at 248 nm,specific detectivity of 3.5×10^(15) Jones,UV-visible rejection ratio of 2.36×10^(4),and total response time of 226.2μs.