Towards highly scaled AlN/GaN-on-silicon devices for millimeter wave applications

In this work, the possibility to achieve GaN-on-Si devices for millimeter wave applications operating at high bias is demonstrated. It is shown that highly scaled AlN/GaN-on-Si double heterostructure enables to significantly improve the electron confinement under high electric field as compared to single heterostructure while delivering high carrier density (> 2×10¹³ cm^-2). Consequently, trapping effects can be minimized resulting in the highest GaN-on-Si output power density at 18 GHz and at a drain bias of 15 V and a record f_max close to 200 GHz. At higher bias, the infrared camera analysis clearly shows that these devices are mainly limited by self-heating. Furthermore, low noise figure has been assessed on this heterostructure, promising integration of cost effective low noise and high power millimeter wave amplifiers.