Huang Yujie, Yang Jing, Zhao Degang, Zhang Yuheng, Liu Zongshun, Liang Feng, Chen Ping
State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
College of Materials Science and Optoelectronics Technology, University of Chinese Academy of Sciences, Beijing 100049, China.
Nanomaterials (Basel). 2023 Jan 28;13(3):525. doi: 10.3390/nano13030525.
The dark leakage current of AlGaN Schottky barrier detectors with different Al contents is investigated. It was found that the dark leakage of AlGaN detectors increased with increasing Al content. The XRD and SIMS results showed that there was no significant difference of the dislocation density and carbon impurity concentration in five AlGaN samples with different Al content. This was likely not the main reason for the difference in dark leakage current of AlGaN detectors. However, the results of positron annihilation showed that the vacancy defect concentration increased with increasing Al content. This was consistent with the result that the dark leakage current increased with increasing Al content. With the increase of vacancy concentration, the vacancy defect energy levels also increased, and the probability of electron tunneling through defect levels increased. In contrast, the Schottky barrier height decreased, which eventually led to the increase of dark leakage current. This discovery should be beneficial to an accurate control of the performance of AlGaN detectors.
研究了不同Al含量的AlGaN肖特基势垒探测器的暗泄漏电流。发现AlGaN探测器的暗泄漏随着Al含量的增加而增大。X射线衍射（XRD）和二次离子质谱（SIMS）结果表明，五个不同Al含量的AlGaN样品中位错密度和碳杂质浓度没有显著差异。这可能不是AlGaN探测器暗泄漏电流差异的主要原因。然而，正电子湮没结果表明，空位缺陷浓度随着Al含量的增加而增加。这与暗泄漏电流随Al含量增加而增大的结果一致。随着空位浓度的增加，空位缺陷能级也增加，电子隧穿缺陷能级的概率增加。相反，肖特基势垒高度降低，最终导致暗泄漏电流增大。这一发现应有助于精确控制AlGaN探测器的性能。
