不同温度下的表面粗糙度对4H-SiC MOSFETs迁移率的影响(英文)

Effect of Surface Roughness on the Channel Mobility of 4H-SiC MOSFETs at Different Temperatures

在制造4H-SiC MOSFETs过程中,超过1 500℃的高温退火用来激活被注入的离子。经常在4H-SiC表面会涂上一层碳膜来进行保护,以此期待4H-SiC MOSFETs取得好的电特性。基于前期4H-SiC MOS电容的实验结果,采用计算机模拟研究了不同温度条件下的表面粗糙度对4H-SiC MOSFETs沟道迁移率的影响。结果表明,在较高的栅压下,限制沟道迁移率的主要机制是表面粗糙度散射,然而,表面粗糙度数值的大小对迁移率的影响不大。结果同时表明,迁移率的峰值会随着温度的增加而增加,然而,对于更高的温度,峰值会随着温度的继续增加而减小。

In the fabrication of 4H-SiC MOSFETs,high temperature annealing is used to activate the implanted ions.Usually,aprotective carbon cap is made to avoid a rough surface on 4H-SiC,and to achieve a good electrical performance for 4H-SiC MOSFETs.In this paper,based on the previous experimental results of the 4H-SiC nMOS capacitor,an extended computer simulation to reveal the effect of surface roughness on the channel mobility of 4H-SiC MOSFETs was carried out at different temperatures.Results show that for a higher gate voltage,the dominant mechanism limiting the channel mobility is the surface roughness scattering,however,the channel mobility is weakly dependent on the scale of surface roughness.The results also show that the peak value of mobility increases with the increasing of temperature,however,after reaching a special temperature,the value will decrease with the increasing of temperature.