Fully Al-based 0.25 µm 20 V GaN-on-Si Process with 3 W/mm for FR3

This paper reports a fully Al-based 0.25 µm GaN-on-Si HEMT process for FR3 application. HEMT transistor was designed in D-mode based on AlGaN/GaN structure equipped with an AlN spacer and a C-doped buffer on an 8-inch high-resistivity silicon wafer. The on-wafer characterizations with the prototyping wafer fabricated show a current collapse (CC) less than 7.5% under gate and drain stress. With a drain voltage of 20 V, the RF power density under 3 dB gain compression at 3.5 and 7 GHz are 3.4 and 3.1 W/mm, respectively. The linearity tests at same two center frequencies with 50 MHz two-tone spacing show the output third-order intercept point (OIP3) are 31 and 34.8 dBm.