论文标题
激子 - 弗朗兹 - 卡尔德斯光电流光谱法中的gan二极管中的局部电场测量
Local Electric Field Measurement in GaN Diodes by exciton Franz-Keldysh Photocurrent Spectroscopy
论文作者
论文摘要
激子Franz-keldysh（XFK）效应是通过光电流响应性数据的光谱变化在GAN P-N结二极管中观察到的，这些响应性数据随着反向偏置的增加而变红并扩大。仅使用一个单个拟合参数来确定线形，局部偏置（$ v_ {l} $），在宽光子能量范围内定量拟合光电流光谱在XFK模型上拟合，从而唯一地确定了局部电场的最大值和耗竭宽度。正如预期的那样，$ v_ {l} $的频谱确定的值随施加的偏置（$ v $）线性变化，并且由于静电不均匀性而显示了当地电场的大幅度降低。内置偏见（$ v_ {bi} $）是通过$ v_ {l} $ at $ v = 0 $来估计的，与独立的C-V测量值相比，这表明总体$ \ pm $ 0.31 V的准确度为$ v_ {l} $。这证明了宽带元件二极管中的局部电场探针，可用于绘制设备分解区域（热点），以改善高压设备的静电设计。
The eXciton Franz-Keldysh (XFK) effect is observed in GaN p-n junction diodes via the spectral variation of photocurrent responsivity data that redshift and broaden with increasing reverse bias. Photocurrent spectra are quantitatively fit over a broad photon energy range to an XFK model using only a single fit parameter that determines the lineshape, the local bias ($V_{l}$), uniquely determining the local electric field maximum and depletion widths. As expected, the spectrally determined values of $V_{l}$ vary linearly with the applied bias ($V$) and reveal a large reduction in the local electric field due to electrostatic non-uniformity. The built-in bias ($V_{bi}$) is estimated by extrapolating $V_{l}$ at $V=0$, which compared with independent C-V measurements indicates an overall $\pm$0.31 V accuracy of $V_{l}$. This demonstrates sub-bandgap photocurrent spectroscopy as a local probe of electric field in wide bandgap diodes that can be used to map out regions of device breakdown (hot spots) for improving electrostatic design of high voltage devices.
