Linearity Characterization of Enhancement- Mode p-GaN Gate Radio-Frequency HEMT

We characterize and evaluate the RF linearity of an enhancement-mode ${p}$ -GaN gate high-electron- mobility-transistor (HEMT) on a 200-mm high-resistivity-silicon substrate. Nearly flat transconductance and its small derivatives, together with relatively uniform small-signal parameters within the operating range, predict good linearity performances of the scaled-down device. With a two-tone technique, the device shows the peak output third-order intercept point (OIP3) of 38.9-dBm at 5 GHz for a 300- $\mu \text{m}$ -gate-width device and the corresponding linearity figure of merit OIP3/ ${P}_{\text {DC}}$ of 14.1-dB. A low power ratio of the third-order intermodulation to the fundamental carrier output (IM3/C) smaller than −50-dBc is also obtained at 8-dB backoff from the single-tone P1dB compression point.