Interstitial oxygen induced Fermi level pinning in the Al2O3-based high-k MISFET with heavy-doped n-type poly-Si gates
Interstitial oxygen induced Fermi level pinning in the Al2O3-based high-k MISFET with heavy-doped n-type poly-Si gates
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DOI：
10.1063/1.4825071
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发表时间：
2013-10-01
期刊：
影响因子：
1.6
通讯作者：
Shiraishi, Kenji
中科院分区：
文献类型：
--
作者：
Yang, Moon Young;Kamiya, Katsumasa;Shiraishi, Kenji
我们通过关注 Al2O3 中间隙氧 (O-i) 形成的影响，研究了在具有 n+多晶硅栅极的 Al2O3 基 MISFET 中观察到的大幅阈值电压 (Vth) 偏移的起源。通过第一性原理计算，我们观察到 Al2O3 中的 O-i 能级比 Al2O3 的价带顶高 1 eV。因此，O-i 的形成以及随后的电子从费米能级到 O-i 能级的转移使得系统能够克服 O-i 形成造成的能量损失，这取决于费米能级的位置。在 n+多晶硅栅极的情况下，会发生跨界面的电子转移并导致显着的 Vth 偏移。所提出的机制再现了实验结果并提供了对纳米界面相互作用的良好理解。 (C) 2013 年作者。除非另有说明，所有文章内容均根据 Creative Commons Attribution 3.0 Unported License 获得许可。
We study the origin of substantial threshold voltage (Vth) shifts observed in Al2O3-based MISFETs with n+poly-Si gate, by focusing on the effect of an interstitial oxygen (O-i) formation in Al2O3. We observed that the O-i level in Al2O3 is 1 eV above the valence band top of Al2O3 by first-principles calculation. Therefore, O-i formation and subsequent electron transfer from Fermi level to the O-i level allows the system to overcome the energy loss by the O-i formation, which depends on the position of Fermi level. In case of n+poly-Si gate, this electron transfer across the interface occurs and results in substantial Vth shifts. The proposed mechanism reproduces experimental result and provides a good understanding of nano-interfacial interactions. (C) 2013 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.