论文标题
将P型GAN转换为N型的螺钉脱位：MG冷凝的显微镜研究和P-N Diodes中的泄漏电流
Screw dislocation that converts p-type GaN to n-type: Microscopic study on the Mg condensation and the leakage current in p-n diodes
论文作者
论文摘要
最近的实验表明，螺纹位错方面的MG凝结会导致电流泄漏，从而导致基于GAN的功率设备降解。为了研究此问题，我们对各种MG和错位复合物进行了第一原理的总能量电子结构计算。我们发现，螺纹螺钉位错（TSD）确实吸引了MG杂质，并且随着MG杂质接近脱位线，由位错引起的能量差距中的电子水平升高朝向传导带，这表明MG-TSD复合物是供体。 MG-TSD复合物的形成是通过我们的原子探针断层扫描明确证明的，其中在P-N二极管中观察到MG缩合和通过[0001]螺钉脱位的扩散。这些发现提供了一种新的图片，即Mg是GAN中的P型杂质，然后向TSD扩散，然后局部形成N型区域。该区域沿TSD的出现导致反向泄漏电流。
Recent experiments suggest that Mg condensation at threading dislocations induce current leakage, leading to degradation of GaN-based power devices. To study this issue, we perform first-principles total-energy electronic-structure calculations for various Mg and dislocation complexes. We find that threading screw dislocations (TSDs) indeed attract Mg impurities, and that the electronic levels in the energy gap induced by the dislocations are elevated towards the conduction band as the Mg impurity approaches the dislocation line, indicating that the Mg-TSD complex is a donor. The formation of the Mg-TSD complex is unequivocally evidenced by our atom probe tomography in which Mg condensation and diffusion through [0001] screw dislocations is observed in p-n diodes. These findings provide a novel picture that the Mg being a p-type impurity in GaN diffuses toward the TSD and then locally forms an n-type region. The appearance of this region along the TSD results the reverse leakage current.
