S波段系列SiC MESFET器件研制

Development of S-Band SiC-MESFETs

SiC材料具有宽禁带、高电子饱和漂移速度、高击穿电压、高热导率和相对低的介电常数等优点，使SiC MESFET在微波功率等方面的应用得到了快速发展。采用国产SiC外延片，解决了欧姆接触、干法刻蚀及损伤修复等一系列工艺难题；针对不同应用背景，研制出总栅宽分别为1、5、15、20mm系列SiCMESFET样管。在2GHz脉冲状态下，300μs脉宽、10％占空比、20mm栅宽器件单胞输出功率超过80W，功率密度大于4W／mm；15mm栅宽器件在3．1～3．4GHZ频带脉冲功率输出超过30W。该研究结果为SiC器件的实用化奠定了基础。

Silicon carbide （SIC） MESFET becomes a very promising candidate for high power microwave applications in commercial and military communications with its excellent properties such as high electric breakdown field, high saturated electron drift velocity and high thermal conductivity. SiC MESFETs with 1 - 20 mm gate periphery were fabricated using a standard SiC epitaxial wafer with the domestic technology. A series of technology problems such as the ohmic contact, dry etching and damage repairing were solved. SiC MESFETs with 1, 5, 15, 20 mm gate periphery were fabricated. SiC MESFETs with 20 mm gate periphery were measured, the output power unit cell is more than 80 W, which corresponds to 4 W/mm at 2 GHz under 300 ms pulse width and 10% duty cycle. SiC MESFETs with 15 mm gate periphery were measured, the output power is more than 30 W at 3.1 - 3.4 GHz under pulse operation. The obtained results lay the solid foundation for the practical applications of SiC power MESFETs.