介绍了一种具有高阈值电压和大栅压摆幅的常关型槽栅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)方法实现Al2O3栅介质的沉积。槽栅常关型AlGaN/GaN MOS-HEMT的栅长(Lg)为2 μm, 栅宽(Wg)为0.9 mm(0.45 mm×2), 栅极和源极(Lgs)之间的距离为5 μm, 栅极和漏极(Lgd)之间的距离为10 μm。在栅压为－20 V时, 槽栅常关型AlGaN/GaN MOS-HEMT的栅漏电仅为0.65 nA。在栅压为+12 V时, 槽栅常关型AlGaN/GaN MOS-HEMT的栅漏电为225 nA。器件的栅压摆幅为－20～+12 V。在栅压Vgs=+10 V时, 槽栅常关型AlGaN/GaN MOS-HEMT电流和饱和电流密度分别达到了98 mA和108 mA/mm (Wg=0.9 mm), 特征导通电阻为4 mΩ·cm2。槽栅常关型AlGaN/GaN MOS-HEMT的阈值电压为+4.6 V, 开启与关断电流比达到了5×108。当Vds=7 V时, 器件的峰值跨导为42 mS/mm (Wg=0.9 mm, Vgs=+10 V)。在Vgs=0 V时, 栅漏间距为10 μm的槽栅常关型AlGaN/GaN MOS-HEMT的关断击穿电压为450 V, 关断泄露电流为0.025 mA/mm。

This essay has reported normally-off operation of an AlGaN/GaN recessed MOS-gate high electron mobility transistor(MOS-gate HEMT) fabricated by the inductively coupled plasma(ICP) recessed technique. A 40-nm Al2O3 film was deposited by the atomic layer deposition(ALD) as the gate dielectric. The normally-off recessed MOS-gate AlGaN/GaN HEMT with a gate length of 2 μm and a gate width of 0.9 mm exhibits a high threshold voltage of +4.6 V, a specific on-resistance of 4 mΩ·cm2 and a drain current density of 108 mA/mm (at a positive gate bias of 10 V). When the gate bias (Vgs) is 0 V, the breakdown voltage(BV) of 450 V has been achieved at a drain leakage current of 0.025 mA/mm for the recessed MOS-gate HEMT with a gate-drain distance of 10 μm. The on/off drain-current ratio (Ion/Ioff) is 5×108 for the recessed MOS-gate HEMT. Under a negative gate bias of -20 V, the gate leakage current of the recessed MOS-gate HEMT was 0.65 nA.