日盲探测器高Al组分n-Al0.6Ga0.4N欧姆接触

研究了应用于目盲探测器的高Al组分Si掺杂n型Al0.6Ga0.4N与两层金属层Ti(20nm)/Al(100nm)之间的欧姆接触.在制作金属电极前用煮沸王水对样片进行表面预处理,会属制作后再在N2氛了围中做快速热退火处理.使用高精度XRD测试样品表面特性,并对不同温度下的情况进行比较.样品的比接触电阻率是用环形传输线模型通过Ⅰ-Ⅴ测试得到.670℃下90s退火得到最优ρc为3.42×10-4n·cm2.将该处理方法应用到实际的背照式AlGaN p-i-n日盲探测器中,探测器的光谱响应度和反向特性等参数得到很大的优化.

Ohmic Contacts to n-Type Al0.6Ga0.4N for Solar-Blind Detectors

We investigate the contact characteristics of bi-layer thin films, Ti(20nm)/Al(200nm) on Si-doped n-type Al0.6Ga0.4 N films grown on sapphire substrate. The surface treatment was aqua regia boiling before metallization and annealing after metallization at different conditions in N2 ambient. High resolution X-ray diffractometery analysis was carried out on the contacts and the surface interfaces of these conditions were compared. A specific contact resistivity ρc was determined using the circular transmission line method via current-voltage measurements. A ρc of 3.42×10-4 Ω·cm2 was achieved when annealed at 670℃ for 90s. Then, this ideal ohmic contact was used in back-illuminated solar-blind AlGaN p-i-n detectors and the detectors' performances, such as spectral responsivity, dark-current, and breakdown voltage were optimized.