Impact of channel thickness scaling on the performance of GaN-on-Si RF HEMTs on highly C-doped GaN buffer

AliReza Alian, Raúl Rodríguez, Sachin Yadav, Uthayasankaran Peralagu, Arturo Sibaja Hernandez, Vamsi Putcha, Ming Zhao, Rana Y. El Kashlan, Bjorn Vermeersch, Hao Yu, Erik Bury, Ahmad Khaled, Nadine Collaert, Bertrand Parvais

Abstract: This work investigates scaling of the GaN channel thickness on top of a carbon-doped GaN buffer (cGaN) grown on 200mm Si substrates. Device performance tradeoffs are analyzed in terms of DC, RF, reliability and thermal behavior. A thinner channel improves DIBL, $I_{off},V_{th}$ roll-off and degrades $f_{T},f_{\max}$, PAE, Pout, charge trapping and thermal conductance characteristics. Transconductance was observed to increase under high saturation drain bias for thin and short channels indicating the lateral device scaling potential of cGaN based HEMTs.