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采用ICP干法刻蚀和PECVD沉积技术,制备了增强型Si衬底SiO2/GaN MOS栅场效应晶体管(MOSFET)。SiO2/GaN MOSFET转移特性曲线测试中出现阈值电压不稳定现象,针对其阈值电压稳定性问题,采用正向电压偏置方法对SiO2/GaN MOSFET的绝缘栅电荷特性展开研究。正向电压偏置后,器件的转移特性曲线和高频C-V特性曲线均正向偏移,研究表明:SiO2/GaN之间存在的界面态和靠近SiO2/GaN界面的SiO2内部陷阱是造成SiO2/GaN MOSFET阈值电压不稳定的原因,实验研究结果同时表明氮气1 000℃快速热退火(RTA)对SiO2内部陷阱有改善作用。
An enhanced Si substrate SiO2 / GaN MOS gate field effect transistor (MOSFET) was fabricated by ICP dry etching and PECVD deposition. The threshold voltage instability occurs in the transfer curve of SiO2 / GaN MOSFETs. In view of the threshold voltage stability, the gate voltage characteristics of SiO2 / GaN MOSFETs are investigated by the forward voltage biasing method. The results show that the interface states between SiO2 / GaN and the internal SiO2 trap near the SiO2 / GaN interface are the main causes for the SiO2 / The reason why the threshold voltage of GaN MOSFET is not stable is shown in the experimental results. It is also shown that RTA at 1 000 ℃ improves the internal trap of SiO2.