Electron Mobility Transistors On AlGaN/GaN Heterostructure with Recess in the Barrier Layer

The influence of thickness of barrier layer nitride heterostructure on characteristics of high electron mobility transistors (HEMT). Reducing thickness of the barrier layer will increase transconductance of transistor, its operating frequencies, gain, and specific output power. In the work, change in thickness of barrier layer of heterostructure due to etching of gate recess. The developed and implemented method of low-energy defectless dry etching of the AlGaN barrier layer is used, which consists in cyclic repetition operations of plasma-chemical oxidation of AlGaN and removal of the oxide layer by means of reactive ion etching in inductively coupled plasma in chlorine-containing medium. AlGaN/AlN/GaN HEMTs with a gate recess were fabricated using the proposed etching method for the first time. It is shown that the currents of obtained transistors are independent of the number of etching cycles, while the gate operating point shifts toward positive voltages (up to obtaining transistors operating in the enhancement mode).