Intrinsic limits to temperature-dependent substrate loss for GaN-on-Si technology, due to the change in resistivity of the substrate with temperature, are evaluated using an experimentally validated device simulation framework. Effect of room temperature substrate resistivity on temperature-dependent CPW line loss at various operating frequency bands are then presented. CPW lines for GaN-on-high resistivity Si are shown to have a pronounced temperature-dependence for temperatures above 150{\deg}C and have lower substrate losses for frequencies above the X-band. On the other hand, GaN-on-low resistivity Si is shown to be more temperature-insensitive and have lower substrate losses than even HR-Si for lower operating frequencies. The effect of various CPW geometries on substrate loss is also presented to generalize the discussion. These results are expected to act as a benchmark for temperature dependent substrate loss in GaN-on-Si RF technology.
@article{arxiv.1901.09521,
title = {Quantifying Temperature-dependent Substrate Loss in GaN-on-Si RF Technology},
author = {Hareesh Chandrasekar and Michael J. Uren and Michael A. Casbon and Hassan Hirshy and Abdalla Eblabla and Khaled Elgaid and James W. Pomeroy and Paul J. Tasker and Martin Kuball},
journal= {arXiv preprint arXiv:1901.09521},
year = {2019}
}