Vertical GaN Power Diodes With a Bilayer Edge Termination
Vertical GaN Power Diodes With a Bilayer Edge Termination
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DOI：
10.1109/ted.2015.2502186
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发表时间：
2016-01-01
影响因子：
3.1
通讯作者：
Wierer, Jonathan J., Jr.
中科院分区：
文献类型：
--
作者：
Dickerson, Jeramy R.;Allerman, Andrew A.;Wierer, Jonathan J., Jr.
采用双层边缘终端（ET）结构制作了垂直GaN功率二极管。GaN p-n结形成在低穿透位错缺陷密度（10（4）~ 10（5）cm（-2））的GaN衬底上，并具有15 μ m厚的自由载流子浓度为5 × 10（15）cm（-3）的n型漂移层。ET结构通过将N注入到p（+）-GaN外延层中恰好在p型接触外部以产生补偿缺陷来形成。注入缺陷分布可以近似为双层结构，该双层结构由表面附近的完全补偿层和随后的n型漂移区附近的90%补偿（p）层组成。这些器件在室温下表现出高达2.6 kV的雪崩击穿。模拟结果表明，通过注入产生的ET是一种有效的方式来横向分布电场在一个大的区域。这增加了发生碰撞电离的电压，并导致观察到更高的击穿电压。
Vertical GaN power diodes with a bilayer edge termination (ET) are demonstrated. The GaN p-n junction is formed on a low threading dislocation defect density (10(4) - 10(5) cm(-2)) GaN substrate, and has a 15-mu m-thick n-type drift layer with a free carrier concentration of 5x10(15) cm(-3). The ET structure is formed by N implantation into the p(+)-GaN epilayer just outside the p-type contact to create compensating defects. The implant defect profile may be approximated by a bilayer structure consisting of a fully compensated layer near the surface, followed by a 90% compensated (p) layer near the n-type drift region. These devices exhibit avalanche breakdown as high as 2.6 kV at room temperature. Simulations show that the ET created by implantation is an effective way to laterally distribute the electric field over a large area. This increases the voltage at which impact ionization occurs and leads to the observed higher breakdown voltages.