氢终端金刚石MOSFET击穿机制的仿真研究

Simulation and Research of the Breakdown Mechanism of Hydrogen-Terminated Diamond MOSFETs

对氢终端金刚石MOSFET进行物理仿真,仿真了栅介质厚度为100 nm的氧化铝栅介质的金刚石MOSFET,得到器件的最大漏电流密度超过400 mA/mm,阈值电压接近20 V,与实测器件性能接近。引入碰撞电离模型,仿真分析了不同结构器件内部电场的分布情况,在栅极边缘和漏电极附近分别出现了电场峰值。通过增加栅介质厚度,可以降低金刚石表面电场强度。大的栅漏间距可以实现更高击穿电压,针对栅介质和金刚石表面的电场尖峰,引入钝化介质和栅场板结构,有效降低了电场峰值,降低了击穿的风险。

The physical simulation of the hydrogen-terminated diamond MOSFET was carried out.The device with an alumina gate dielectric of 100 nm thickness was simulated,and the maximum drain current density of over 400 mA/mm and the threshold voltage of about 20 V were obtained,which were close to performances of the tested device.By introducing the compact ionization model,internal electric field distribution of devices with different structures were simulated and analyzed.There are two electric field peaks appearing at the gate edge and near the drain electrode respectively.By increasing the thickness of the gate dielectric,the electric field strength on the diamond surface can be reduced.A higher breakdown voltage can be achieved with a larger gate-drain distance.For the peaks of the electric field on the gate dielectric and diamond surface,passivation dielectric and gate field plate structure are introduced,which effectively reduce the electric field peak and reduce the risk of breakdown.