Abstract

We present dispersion free pulsed current voltage (I-V) and radio frequency (RF) power results of undoped and doped AlGaN/GaN HEMTs on sapphire and SiC substrates. The most significant processing step leading to these results is the application of a reactive ion etching (RIE) argon (Ar) plasma (10sccm, 40mTorr, 20W, t=30s, DC bias = -167V, 20 C) to the AlGaN surface before annealing of the ohmic contacts and surface passivation with plasma enhanced chemical vapor deposition (PECVD) silicon nitride (SiNx). In addition, this process strongly improves the uniformity of RF device performance and is independent of the material source.