平面型GaN p-n结探测器的制备与性能

摘要

The annealing temperature dependence of FWHM of X-ray rocking curves of p-GaN layers grown on sapphire substrate by metal organic chemical vapor deposition (MOCVD) were studied. The results show that the quality of p-GaN became worse at annealing temperature higher than 1150℃. The implantation conditions were simulated by TRIM. The planar GaN p-n detectors were fabricated by Si implantation into p-GaN. The current-voltage (Ⅰ-Ⅴ) curve at room temperature shows that the dark current density is 4.7nA/cm2 at zero voltage bias. The peak responsivity is 0.065 A/W and 0.039A/W at 368 nm at room temperature and 80 K, respectively. It decreases obviously with the decrease of temperature as a result of the changes in bandgap, series resistance, and build-in potential with temperature.%采用金属有机物化学气相沉积(MOCVD)方法在蓝宝石衬底上制备了p-GaN单晶薄膜.高温(＞1100℃)处理及未处理样品的双晶摇摆曲线测试表明高于1150℃会使材料的晶体质量明显变差,这为平面型紫外探测器制备中的部分注入激活条件提供了选择依据.通过TRIM软件优化了注入条件,在选择性注入改型材料上成功制备了平面GaN p-n结型光电探测器.测试结果表明:室温下的零偏压暗电流密度为4.7 nA/cm2,而-5 V偏压下的暗电流密度则达到了67 μA/cm2.室温下的峰值响应率0.065A/W出现在368 nm处.在低温下器件的峰值响应明显降低,80 K时,360nm处的峰值响应率仅为0.039A/W.禁带宽度、串联电阻、内建电场等是引起探测器响应率随温度降低的原因.