具有高开启/关断电流比的Al2O3/AlGaN/GaN金属氧化物半导体高电子迁移率晶体管

采用原子层淀积(ALD)方法,制备了Al₂O₃为栅介质的高性能AlGaN/GaN金属氧化物半导体高电子迁移率晶体管(MOS-HEMT)。在栅压为-20 V时,MOS-HEMT的栅漏电比Schottky-gate HEMT的栅漏电低4个数量级以上。在栅压为+2 V时,Schottky-gate HEMT的栅漏电为191μA;在栅压为+20 V时,MOS-HEMT的栅漏电仅为23.6 nA,比同样尺寸的Schottky-gate HEMT的栅漏电低将近7个数量级。AlGaN/GaN MOS-HEMT的栅压摆幅达到了±20 V。在栅压V_gs=0 V时, MOS-HEMT的饱和电流密度达到了646 mA/mm,相比Schottky-gate HEMT的饱和电流密度(277 mA/mm)提高了133%。栅漏间距为10μm的AlGaN/GaN MOS-HEMT器件在栅压为+3 V时的最大饱和输出电流达到680 mA/mm,特征导通电阻为1.47 mΩ·cm²。Schottky-gate HEMT的开启与关断电流比仅为10⁵,MOS-HEMT的开启与关断电流比超过了10⁹,超出了Schottky-gate HEMT器件4个数量级,原因是栅漏电的降低提高了MOS-HEMT的开启与关断电流比。在V_gs=-14 V时,栅漏间距为10μm的AlGaN/GaN MOS-HEMT的关断击穿电压为640 V,关断泄露电流为27μA/mm。

Al2O3/AlGaN/GaN MOS-HEMT with High On/Off Drain Current Ratio

This essay has reported the fabrication of a metal-oxide-semiconductor AlGaN/GaN high electron mobility transistor ( MOS-HEMT ) with an Al2 O3 insulator layer which was deposited by atomic layer deposition ( ALD) as the gate dielectric. The MOS-HEMT with a gate-drain distance of 10 μm exhibits a drive current density of 680 mA/mm at a gate-source bias ( Vgs ) of +3 V and a specific on-resistance of 1. 47 mΩ·cm2 . Under a negative gate bias of -20 V, the gate leakage current of the MOS HEMT is over four orders of magnitude, which is lower than that of the Schottky-gate HEMT. The off-state breakdown voltage is 640 V at drain leakage current of 27 μA/mm with Vgs = -14 V. The Schottky-gate HEMT leakage current is 191 μA at the gate bias of +2 V and the MOS HEMT leakage current is as low as 23. 6 nA at the gate bias of +20 V, which is approximately seven orders of magnitude lower than that of the Schottky-gate HEMT with similar gate dimensions. The on/off drain-current ratio ( Ion/Iof ) is over 109 for the MOS-HEMT.