4H-SiCMESFET频率特性研究

Research on the frequency performance of 4H-SiC MESFET

研究了4H-SiCMESFET的频率特性与器件几何及物理参数的关系。发现常温300K时,4H-SiCMESFET的截止频率随沟道掺杂浓度增加而上升;随沟道厚度的增加而降低;随栅长的增加而下降;随工作温度的增加变化很小,500K以上时略有降低。300K下,在沟道掺杂为4×1017cm-3、沟道厚度为0.25mm、栅长0.30mm、栅压偏置为-5V时,模拟得到的截止频率fT达到18.62GHz,显示该器件在高频、高温、大功率领域的极大优越性和应用前景。

In this article, frequency performance of 4H-SiC MESFET versus it’s geometry andphysical parameters is well researched. At normal temperature (300K), cutoff frequency fT of 4H-SiCMESFET rises as the impurity concentration of channel increases. The fT behaves a decline trendwhile the depth of channel increases and fT falls as the gate becomes longer. When operationtemperature goes higher, the cutoff frequency of 4H-SiC changes a little and it shows a slight declinewhen the temperature is above 500K. At 300K, a 18.62 GHz cutoff-frequency has been acquired bysimulation with impurity concentration at 4×1017cm-3, channel depth at 0.25 mm, gate length at 0.30mm and a applied gate voltage at –5V, therefore this device exhibits a tremendous potential in high-frequency, high-temperature and high-power areas.