Improvement of linearity in GaN high electron mobility transistors by incorporation of a reverse Schottky barrier at source access region

In this work, we propose and experimentally demonstrate a GaN high electron mobility transistor (HEMT) with improved linearity by incorporating a reverse Schottky barrier at the source access region. Simulation and experimental results show effective suppression of the source access resistance (RS) increase at high channel current levels in the proposed device. The fabricated AlN/GaN HEMT on Si with a reverse Schottky-barrier source (RSS-HEMT) shows a flatter transconductance (gm) profile vs gate voltage (VG), compared to the conventional device. The peak of the second-order derivative of transconductance (gm″) in the proposed RSS-HEMT is reduced by 66%. Two-tone intermodulation distortion measurement at a center frequency of 10 GHz demonstrates a high third-order output intercept point/DC power (OIP3/PDC) of up to 12.6 dB. These results show the great potential of the proposed technique for high-linearity radio frequency applications.