Towards millimeter-wave high PAE high power using ultrathin Al-rich barrier GaN devices

We report on the development of an emerging AlN/GaN/AlGaN double heterostructure for millimeter-wave applications. These types of novel heterostructures are indeed extremely promising for high frequency applications, however, limited today in terms of drain bias operation typically around 20 V and power-added-efficiency (PAE). In this work, high RF output power density at drain bias above 30 V is demonstrated for the first time on a 6 nm ultrathin barrier AlN/GaN double heterostructure. Furthermore, state-of-the-art PAE has been achieved up to 40 GHz owing to the control of device leakage current, material and processing quality and current collapse under high electric field in spite of the very close proximity of the surface charges and the 2DEG.