增强型AlGaN/GaN/AlGaN双异质结槽栅HEMT研究

Study of Enhancement-Mode AlGaN/GaN/AlGaN Double Heterojunction Recessed-Gate HEMT

为了在获得高击穿电压的同时实现增强型器件,对AlGaN/GaN/AlGaN双异质结HEMT进行了栅槽刻蚀,得到阈值电压为0.6 V的增强型HEMT。对器件特性的变化机理进行了分析,发现刻蚀引入的陷阱态使器件的击穿性能降低。采用变频电导法,定量研究了反应离子刻蚀在AlGaN/GaN/AlGaN双异质结HEMT中引入的陷阱态。研究表明,刻蚀工艺在双异质结HEMT中引入了大量的浅能级陷阱,这些陷阱的能级主要分布在0.36～0.40 eV。

In order to achieve an enhancement-mode device with high breakdown voltage,a gate recess etching for AlGaN/GaN/AlGaN double heterojunction HEMT devices was carried out.An enhanced HEMT device with a threshold voltage of 0.6 V was obtained,and the change mechanism of the device characteristics was analyzed and explained.The trap states induced by etching had deteriorated the breakdown characteristics of the device.Frequency-dependent conductance measurements were carried out to investigate quantitatively the trap states induced by reactive ion etching in AlGaN/GaN/AlGaN double heterojunction HEMTs.It was shown that lots of trap states with shallow energy levels were induced by the gate recess etching for the double heterojunction HEMT,and the trap states were located at energy levels in a range of 0.36~0.40 eV for the recessed double heterojunction HEMT.