The RF harmonic distortion of coplanar waveguides (CPWs) fabricated on AlGaN/GaN HEMT heterostructures grown on both high-resistivity Si (GaN-on-Si) and semi-insulating SiC (GaN-on-SiC) substrates is reported for the first time. The loss performance and the nonlinear behavior of the CPW lines were experimentally characterized using both small- and large-signal measurements. From 100 MHz to 20 GHz, low loss (less than 0.3 dB/mm at 20 GHz) was achieved; the attenuation of CPW lines on the GaN-on-Si substrate is ~0.05 dB/mm higher than that of the GaN-on-SiC substrate. The harmonic distortion levels of the GaN-on-Si substrate and GaN-on-SiC were also evaluated experimentally; in contrast to the small-signal loss, more significant differences in second- and third-order nonlinearity, and thus intermodulation, are observed between Si and SiC substrates. Large-signal characterization of the GaN-on-Si substrate was carried out over temperature from 25 °C to 175 °C. Due to increases in substrate conductivity with temperature, the harmonic distortion levels are found to increase significantly at temperatures above 75 °C.
RF Harmonic Distortion of Coplanar Waveguides on GaN-on-Si and GaN-on-SiC SubstratesPatrick Fay, University of Notre DameLina Cao, University of Notre DameHansheng Ye, University of Notre DameJingshan Wang, Notre DameHugues Marchand, IQEWayne Johnson, IQEDownload Paper
16.5 Epitaxial Lift-Off from Native GaN Substrates Using Photoenhanced Wet EtchingChris Youtsey, MicroLink Devices, Inc.Robert McCarthy, MicroLink DevicesRekha Reddy, MicroLink DevicesAndy Xie, QorvoEd Beam, QorvoJingshan Wang, Notre DamePatrick Fay, University of Notre DameEric Carlson, Virginia TechLou Guido, Virginia Tech