AlGaN/GaN Heterostructure Field-Effect Transistor with Semi-Insulating Mg-Doped GaN Cap Layer

摘要

Technology, Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, TaiwanWe report the fabrication of AlGaN/GaN heterostructure field-effect transistor (HFET) with in situ grown semi-insulating Mg-doped GaN (GaN:Mg) cap layer. Without activation, the GaN:Mg film is known to be highly resistive and shown to reduce leakage current in AlGaN/GaN heterostructure. With l-μm-long gate length at drain-voltage of 10V, the presented HFET exhibited a drain-source current in saturation (I_(DSS)) of 735 mA/mm and a peak transconductance g_(m(max)) of 170 mS/mm, while the current gain cutoff frequency (f_T) and maximum frequency of oscillation (fmax) were 20.5 and 33.3 GHz, respectively.