Quantum-Transport Study on the Impact of Channel Length and Cross Sections on Variability Induced by Random Discrete Dopants in Narrow Gate-All-Around Silicon Nanowire Transistors
Quantum-Transport Study on the Impact of Channel Length and Cross Sections on Variability Induced by Random Discrete Dopants in Narrow Gate-All-Around Silicon Nanowire Transistors
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DOI：
10.1109/ted.2011.2157929
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发表时间：
2011-07
影响因子：
3.1
通讯作者：
A. Martinez;M. Aldegunde;N. Seoane;A. Brown;J. Barker;A. Asenov
中科院分区：
文献类型：
--
作者：
A. Martinez;M. Aldegunde;N. Seoane;A. Brown;J. Barker;A. Asenov
在本文中，我们回顾和扩展最近的工作随机离散掺杂剂的影响，在栅极全包围硅纳米线晶体管的统计变异性。电子输运的描述使用非平衡绿色函数形式主义。采用全三维实空间和耦合模空间表示。两个不同的横截面（即，2.2× 2.2和4.2 × 4.2 nm 2）和两种不同的沟道长度（即，6和12 nm）。与离散掺杂剂相关联的电阻率可以从平均电流-电压特性估计。沟道长度越长，阈值电压变化率和亚阈值斜率变化率越小。在2.2 × 2.2 nm 2器件中，由于静电完整性更好，两者在等效沟道长度下都更小。同时，与存取区的变化电阻相关联的导通状态电流变化性实际上与沟道长度无关。然而，在4.2 × 4.2 nm 2晶体管中，由于存取区中掺杂物的数量增加了四倍以及相应的自平均效应，它大大降低。最后，我们给出了结合两个可变性来源（即，离散的随机掺杂剂和表面粗糙度）和声子散射。
In this paper, we review and extend recent work on the effect of random discrete dopants on the statistical variability in gate-all-around silicon nanowire transistors. The electron transport is described using the nonequilibrium Green's function formalism. Full 3-D real-space and coupled-mode-space repre sentations are used. Two different cross sections (i.e., 2.2 × 2.2 and 4.2 × 4.2 nm2) and two different channel lengths (i.e., 6 and 12 nm) have been considered. The resistivity associated with discrete dopants can be estimated from the averaged current-voltage characteristics. The threshold-voltage variability and the sub threshold-slope variability are reduced greatly in the transistors with longer channel length. Both are smaller at equivalent channel lengths in the 2.2 × 2.2 nm2 device due to better electrostatic integrity. At the same time, the ON-state-current variability associated with the varying resistance of the access regions is virtually independent of the channel length. However, it is reduced greatly in the 4.2 × 4.2 nm2 transistor due to a fourfold increase in the number of dopants in the access regions and corresponding self-averaging effects. Finally, we present results for the smallest transistor combining two sources of variability (i.e., discrete random dopants and surface roughness) and phonon scattering.