Characterization of Vth‐instability in Al2O3/GaN/AlGaN/GaN MIS‐HEMTs by quasi‐static C‐V measurement
Characterization of Vth‐instability in Al2O3/GaN/AlGaN/GaN MIS‐HEMTs by quasi‐static C‐V measurement
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DOI：
10.1002/pssc.201100302
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发表时间：
2012-03
期刊：
影响因子：
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通讯作者：
Sen Huang;Shu Yang;J. Roberts;K. J. Chen
中科院分区：
文献类型：
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作者：
Sen Huang;Shu Yang;J. Roberts;K. J. Chen
通过直流电流-电压 (I-V)、高频电容-电压 (C-V) (HFCV) 和准静态 C-V (QSCV) 表征系统地研究了以 ALD-Al2O3 (15 nm) 作为栅极电介质的 AlGaN/GaN MIS-HEMT 的阈值电压 (Vth) 不稳定性。对于 Al2O3/GaN/AlGaN/GaN MIS 二极管，如果最大正向偏压 (VF,max) 仅设置为 0 V，则双模（上下扫描）HFCV 测量中会出现微小的 Vth 迟滞 (ΔVth)，而当 VF,max 增加至 +5 V 时，会出现明显的顺时针 ΔVth（大至 0.9 V）。因此，通过增加双模传输特性测量中的最大VGS (VGS,max)。一旦 VGS,max 超过 +1.1 V，也会出现显着的顺时针 ΔVth，并且在 VGS,max= +3 V 时增加至~1 V。AlGaN/GaN HEMT 中不存在这种 Vth 不稳定性。研究表明，Al2O3/GaN 界面处的类受主深态是 Al2O3/GaN/AlGaN/GaN MIS-HEMT 中 Vth 不稳定性的原因，并且 QSCV 测量成功捕获了它们的填充和发射过程。使用 1 Hz QSCV 检测到的界面态密度约为 4.6×1012 cm-2。 （© 2012 WILEY-VCH Verlag GmbH & Co. KGaA，魏因海姆）
The threshold-voltage (Vth) instability in AlGaN/GaN MIS-HEMTs with ALD-Al2O3 (15 nm) as gate dielectrics is systematically investigated by dc current-voltage (I-V), high-frequency capacitance-voltage (C-V) (HFCV), and quasi-static C-V (QSCV) characterizations. For Al2O3/GaN/AlGaN/GaN MIS diodes, tiny Vth hysteresis (ΔVth) appears in double-mode (up and down sweep) HFCV measurements if the maximum forward bias (VF,max) is only set to 0 V, while an apparent clockwise ΔVth (as large as 0.9 V) emerges as VF,max is increased to +5 V. The stability of Vth in the corresponding MIS-HEMTs is thus studied by increasing the maximum VGS (VGS,max) in the measurement of double-mode transfer characteristics. Significant clockwise ΔVth also occurred once the VGS,max exceeds +1.1 V, and it increased to ∼1 V at VGS,max= +3 V. Such Vth-instability is absent in AlGaN/GaN HEMTs. It is suggested that the acceptor-like deep states at Al2O3/GaN interface account for the Vth-instability in Al2O3/GaN/AlGaN/GaN MIS-HEMTs, and their filling and emission processes are successfully captured by QSCV measurements. The interface state density detected is about 4.6×1012 cm-2 using 1 Hz QSCV. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)