4H-SiC Planar MESFETs on High-Purity Semi-Insulating Substrates
Planar MESFETs were fabricated on high-purity semi-insulating (HPSI) 4H-SiC substrates. The saturation drain current of the fabricated MESFETs with a gate length of 0.5 μm and a gate width of 100 μm was 430 mA/mm, and the transconductance was 25 mS/mm. The maximum oscillation frequency and cut-off frequency were 26.4 GHz and 7.2 GHz, respectively. The power gain was 8.4 dB and the maximum output power density was 2.8 W/mm for operation of class A at CW 2 GHz. MESFETs on HPSI substrates showed no current instability and much higher output power density in comparison to MESFETs on vanadium-doped SI substrates.
N. Wright, C.M. Johnson, K. Vassilevski, I. Nikitina and A. Horsfall
J. H. Yim et al., "4H-SiC Planar MESFETs on High-Purity Semi-Insulating Substrates", Materials Science Forum, Vols. 556-557, pp. 763-766, 2007