Regrown Vertical GaN p–n Diodes with Low Reverse Leakage Current
Regrown Vertical GaN p–n Diodes with Low Reverse Leakage Current
复制标题
具有低反向漏电流的再生长垂直 GaN p-n 二极管
DOI：
--
复制
发表时间：
2019
影响因子：
2.1
通讯作者：
V. Abate
中科院分区：
文献类型：
--
作者：
G. Pickrell;A. Armstrong;A. Allerman;M. Crawford;K. Cross;C. Glaser;V. Abate
报道了垂直c面GaN p-n二极管，其中p-GaN层通过使用金属有机化学气相沉积的外延再生长形成。电流-电压（I-V）性能与连续生长的p-n二极管类似，包括低反向漏电流和超过−600 V的反向击穿电压，尽管缺乏场管理结构来增加反向击穿电压。再生界面的二次离子质谱分析揭示，在再生界面处的Si的主要来源（“Si尖峰”）是在装载用于再生之前的晶片处理期间的非原位污染。连续生长的p-n二极管，在p-n结处故意掺杂Si，当Si片浓度< 8 × 1011 cm−2时，其I-V性能不会降低。其中在p-GaN再生长之前对n型漂移层进行（等离子体）干法蚀刻的再生长二极管表现出显著更高的反向漏电流。从这些结果中，我们得出结论，Si < 8 × 1011 cm−2的存在和外延再生长工艺不是性能下降的原因。在外延再生长之前去除干法蚀刻引起的电流泄漏机制应该能够实现用于选择性区域p型掺杂控制的方法，该方法可以导致实现高性能垂直功率晶体管。
Vertical c-plane GaN p–n diodes, where the p-GaN layer is formed by epitaxial regrowth using metal–organic chemical-vapor deposition, are reported. Current–voltage (I–V) performance similar to continuously grown p–n diodes is demonstrated, including low reverse leakage current and reverse breakdown voltage in excess of −600 V, despite the lack of field management structures to increase the reverse breakdown voltage. Secondary-ion mass spectrometry analysis of regrown interfaces reveals that the primary source of Si at the regrown interface (“Si spike”) is ex situ contamination during wafer handling prior to loading for regrowth. Continuously grown p–n diodes with intentional Si doping at the p–n junction do not show degraded I–V performance for Si sheet concentrations < 8 × 1011 cm−2. Regrown diodes where the n-type drift layer is (plasma) dry-etched before p-GaN regrowth demonstrate significantly higher reverse leakage current. From these results, we conclude that the presence of Si < 8 × 1011 cm−2 and the epitaxial regrowth process are not responsible for performance degradation. Removal of dry-etch-induced current leakage mechanisms, prior to epitaxial regrowth, should enable a method for selective-area p-type doping control that could lead to realization of high-performance vertical power transistors.