温度对AlGaN/GaN HEMT电学性能的影响

研究了蓝宝石衬底AlGaN/GaN HEMT器件直流和微波性能随温度的变化。研究结果表明,器件直流性能随着温度升高逐渐下降,350°C时直流性能依然良好,从350°C冷却到室温后,器件直流特性除欧姆接触电阻改善外,其他都得到了恢复;微波测试表明,器件fT,fmax都随温度升高而下降,180°C时,fT从室温的11.6GHz下降为7.5GHz、fmax从24.6GHz下降为19GHz,通过外推得到350°C时的fT为3.5GHz,fmax为12GHz。证明了AlGaN/GaN HEMT具有良好的热稳定性,适合在高温下进行高频工作。

Temperature Dependence on DC and RF Performance of AlGaN/GaN HEMTs

Temperature dependence on DC and RF performance of AlGaN/GaN HEMTs fabricated on sapphire substrate has been researched in this paper. DC characteristics were measured from room temperature to 350°C and the DC performance gradually degraded with the increasing of temperature. After the device was cooled down from 350°C to room temperature, the DC performance recovered completely and the ohmic contact resistance got some improvement. RF performance was characterized from room temperature to 180°C. The current gain cut-off frequency was decreased from 11.6 GHz at room temperature to 7.5 GHz at 180°C and the maximum oscillation frequency was decreased from 24.6 GHz to 19 GHz. A cut-off frequency of 3.5 GHz and a maximum oscillation frequency of 12 GHz at 350°C can be obtained by extrapolation. The measured results revealed that AlGaN/GaN HEMTs have high thermal stability up to 350°C and are suitable for high temperature RF application.