摘要
通过在GaN缓冲层上先生长一层20 nm厚的AlN插入层,成功地在此插入层上生长出了200 nm厚的AlxGa1-xN(0.22<x<0.28)材料。研究并优化了AlxGa1-xN材料上的Ti/Al/Ni/Au欧姆接触和Ni基肖特基接触的形成条件。20 nm/150 nm/20 nm/200 nm的Ti/Al/Ni/Au金属层在N2氛围中,700℃下,快速热退火处理120 s后,其欧姆接触的比接触电阻率为3.13×10-5Ω.cm2。研究表明,当AlxGa1-xN材料中Al组分x>0.20时,其上Ni基肖特基势垒高度几乎是不变的。在O2氛围中,300℃下,对AlxGa1-xN材料上10 nm厚的金属Ni层氧化90 s,得到了此Ni层在314 nm的透射率由57.5%提高到78.2%。在器件的光电流谱测量中,得到了器件最短的截止波长为307 nm,紫外/可见光达到103以上。
Followed by depositing 20 nm wide AlN interlayer on the GaN buffer, 200 nm wide AlxGa1-xN （0.22〈x〈0.28） was successfully extended. The conditions of Ohmic contacts formed by Ti/Al/Ni/Au layers and Schottky contacts formed by Ni layer were researched and optimized. The Ohmic resistance of Ti/Al/Ni/Au （20 nm/150 nm/20 nm/200nm） annealed in the N2 ambience,700 ℃ for 120 s is 3. 13 × 10^-5Ω· cm^2. It is demonstrated that when the Al mole fraction of AlxGa1-xN is more than 0.20, the Schottky Barrier Height between metal Ni layer and Al1Ga1-xN is almost the same. When 10 nm wide Ni deposited on the AlxGa1-xN is oxidated in O2 ambience ,300 ℃ for 90 s, the transmission coefficient increases from 57.5% to 78.2% at the wavelength of 314 nm. Consequently, AlxGa1-xN-based UV photodetectors with different cut-off wavelength are obtained. The shortest wavelength of these detectors is 307 nm, and the UV/ visible ratio is 3 orders of magnitude.
出处
《半导体光电》
EI
CAS
CSCD
北大核心
2007年第6期789-792,共4页
Semiconductor Optoelectronics
基金
国家自然科学基金资助项目(60476028)
