Improved RF Characteristics of AlGaN/AlN/GaN HEMT by using 3C-SiC/Si Substrate

This study investigates the AlGaN/AlN/GaN high electron mobility transistor (HEMT) epitaxial layers grown 3C-SiC/Si substrate. The SiC was grown between GaN Buffer layer and Si substrate. In the X-ray-diffraction, the lower FWHM value of SiC on Si HEMT shows less dislocation density. Furthermore, SiC on Si HEMT has a similar coefficient of thermal expansion (CTE) and lattice size with GaN, so it has fewer traps. Because of this reason, the characteristic of DC measurements has good performance. The gmmax values of SiC on Si HEMT is 147 mS/mm, IDSmax= 598 mA/mm and Ron=4.63 Ω ∙ mm. High-Frequency measurement of SiC on Si operate on VDS=10 V, VGS= −1.3 V, and the current gain cutoff frequency of SiC on Si HEMT is 2.6 GHz Maximum Frequency of Oscillation of SiC on Si HEMT is 5.3 GHZ. Therefore, GaN HEMTs SiC grown on Si substrate improve the lattice matching and improve the characteristic performance.