栅极偏置对SiC MOSFET总剂量效应的影响及加固

Influence and reinforcement of gate bias on total dose effect of SiC MOSFET

文章针对总剂量效应造成的MOSFET阈值漂移问题,使用1 200 V SiC MOSFET进行辐照试验,对栅极偏压和辐照后高温栅极偏置退火对阈值漂移的影响和原理进行了研究。通过中带电压法分析发现,造成阈值电压负向漂移的主要原因是辐照产生的空穴被近界面陷阱俘获。通过对不同栅极氧化层退火条件制备的SiC MOSFET试验和分析,得出了当使用氮化气体退火进行总剂量效应加固时,需要折中考虑对沟道迁移率的影响;在5%氮化气体体积分数、1 300℃下退火60 min的条件下制备出来的SiC MOSFET沟道迁移率较高,并且抗总剂量效应能力较强。

To address the MOSFETs threshold drift caused by the total dose effect,1200 V SiC MOSFETs were used for irradiation experiments.The effect and mechanism of gate bias voltage and high-temperature gate bias annealing after irradiation on the threshold drift of MOSFETs were investigated.Through the analysis using the midband voltage method,it was found that the negative threshold drift was mainly caused by the capture of the irradiation-generated holes by near-interface traps.Experiments and analysis on SiC MOSFETs prepared with different gate oxide annealing conditions revealed that a compromise was needed to consider the effect on channel mobility when performing total dose effect reinforcement by nitride gas annealing.And it was found that the MOSFETs prepared under the annealing condition of 5%nitride gas fraction and 60 min at 1300°C had high channel mobility and strong resistance to total dose effect.