制备了一种与Si-CMOS工艺线兼容的AlGaN/GaN HEMTs低温无金欧姆接触电极,分析了欧姆前刻槽深度和退火合金条件对Si基AlGaN/GaN异质结无金欧姆接触特性的影响。系统研究了具有不同欧姆前刻槽深度、不同退火条件的AlGaN/GaN异质结的Ti/Al/Ti/TiW无金电极的电流-电压特性、接触电阻率以及电极表面形貌。并利用低温退火的Ti/Al/Ti/TiW无金工艺制备了AlGaN/GaN异质结MISHEMT器件。实验结果表明,采用该无金工艺可得到比接触电阻率为5.44×10-5 Ω·cm2、表面形态平整的欧姆接触电极,所制备的AlGaN/GaN异质结MISHEMT器件,在VGS=0 V时的源漏饱和电流(IDSS)为345.7 mA/mm,对未掺杂AlGaN/GaN HEMTs器件的低温无金欧姆接触的实现具有指导意义。

An AlGaN/GaN HEMTs low temperature Au-free ohmic contact electrode is prepared, which is compatible with Si-CMOS production line. The effects of the depth of pre-ohmic recess and the annealing alloy condition on the Au-free ohmic contact characteristics of Si-based AlGaN/GaN heterojunction are analyzed. The current-voltage characteristics, contact resistivity and surface morphology of the Ti/Al/Ti/TiW Au-free contact electrodes with different ohmic recess and annealing conditions are systematically investigated. AlGaN/GaN MISHEMTs are fabricated by low temperature annealed Ti/Al/Ti/TiW Au-free process. The experimental results show that the ohmic contact electrodes with contact resistivity of 5.44×10-5 Ω·cm2 and smooth surface morphology can be obtained by using Au-free process. The source and drain saturation current of this device is IDSS=345.7 mA/mm at gate-source voltage VGS=0 V. It is of great significance for the realization of low temperature Au-free ohmic contact process for undoped AlGaN/GaN HEMTs devices.