  High voltage (~2 kV) AlGaN-channel HEMTs were fabricated with 64% Aluminum
composition in the channel. The average on-resistance was ~75 ohm. mm (~21
miliohm. cm^2) for LGD = 20 microns. Breakdown voltage reached >3 kV (tool
limit) before passivation however it reduced to ~2 kV after SiN surface
passivation and field plates. The apparent high breakdown voltage prior to
passivation can possibly be attributed to the field plate effect of the charged
trap states of the surface. The breakdown voltage and RON demonstrated a strong
linear correlation in a scattered plot with ~50 measured transistors. In pulsed
IV measurements with 100 microsecond pulse width and 40 V of off-state bias
(tool limit), the dynamic RON increased by ~5% compared to DC RON and current
collapse was <10%.
