运用一种量子模型研究对高k介质纳米MOSFET的栅电流进行了模拟计算，该模型基于Schrödinger-Poisson方程自洽全量子数值解，对栅电流中的三维电流成分用行波统一地计算热发射电流、通过介质势垒的FN (Fowler- Nordheim) 隧穿电流，直接隧穿电流，带间隧穿电流；对二维栅电流成分通过反型层势阱中准束缚态的隧穿率计算。运用该方法计算了各种结构和材料高k介质的MOSFET栅极电流, 并进行了分析比较。模拟得出栅极电流与实验结果符合。
Simulation of Gate Current for Nanoscale MOSFETs with High-k Stacks
We use a quantum-mechanical model to study the gate tunneling current ofhigh-k dielectric films for nanoscale MOSFETs.This model is based on fully self-consistent solutions to the Schrödinger- Poisson equations. The three-dimensional gate current component evaluation is performed by the traveling wave calculations for the thermionic emission, Fowler-Nordheim (FN) tunneling, and direct tunneling through the oxide barrier. For the two-dimensional gate current component originated from the subbands in the inversion layers, a transmission calculation is performed. Various structures and materials of high-k stacks of interest have been examined and compared to access the reduction of gate current in these structures. The results of gate current obtained from our model are in very good agreement with experimental data.
Fig.1 Schematic gate current components in nanoscale MOS structure
Fig. 2 Comparison of simulated and experimental results for SiO2 gate dielectric films
Reference:
W. Wang, N. Gu, J. P. Sun , and P. Mazumder, “Gate current modeling of high-k stack nanoscale MOSFETs,”Solid-State Electronics, vol. 50, pp.1489–1494, 2006.
