A New Post Annealing Method for AlGaN/GaN Heterostructure Field-Effect Transistors Employing XeCl Excimer Laser Pulses

摘要

A new post annealing method employing excimer laser pulses is proposed to improve the transfer characteristics and the breakdown voltage of the unpassivated AlGaN/GaN heterostructure field-effect transistor(HFET)and the passivated one.The XeCl excimer laser pulses with wavelength of 308 nm anneal the AlGaN/GaN HFET after the Schottky gate metallization.The interface defects between the Schottky gate metal and a GaN layer is decreased by the lateral heat diffusion of the laser pulses.Our experimental results show that the drain current and the maximum transconductance of the unpassivated AlGaN/GaN HFET after laser pulses annealing are 496 mA/mm and 134 mS/mm while a virgin device shows 434 mA/mm and 113 mS/mm,respectively.The proposed method anneals effectively the SiO_2 passivated AlGaN/GaN HFET and the leakage current of the passivated device is decreased from 483 nA to 29 nA.