AlN/GaN heterostructures with 1700-cm(2)/V . s Hall mobility have been grown by molecular beam epitaxy on freestanding GaN substrates. Submicrometer gate-length (L-G) metal-oxide-semiconductor (MOS) high-electron-mobility transistors (HEMTs) fabricated from this material show excellent dc and RF performance. L-G = 100 nm devices exhibited a drain current density of 1.5 A/mm, current gain cutoff frequency f(T) of 165 GHz, a maximum frequency of oscillation f(max) of 171 GHz, and intrinsic average electron velocity v(e) of 1.5 x 10(7) cm/s. The 40-GHz load-pull measurements of L-G = 140 nm devices showed 1-W/mm output power, with a 4.6-dB gain and 17% power-added efficiency. GaN substrates provide a way of achieving high mobility, high v(e), and high RF performance in AlN/GaN transistors.
High Electron Velocity Submicrometer AlN/GaN MOS-HEMTs on Freestanding GaN Substrates
Meyer, D. J., Deen, D. A., Storm, D. F., Ancona, M. G., Katzer, D. S., Bass, R., ... Evans, K. R. (2013). High Electron Velocity Submicrometer AlN/GaN MOS-HEMTs on Freestanding GaN Substrates. IEEE Electron Device Letters, 34(2), 199-201. https://doi.org/10.1109/LED.2012.2228463