速度過衝減弱化之超短通道雙閘極金氧半場效電晶體

Abstract

近幾年來，如何微縮半導體元件是個極具挑戰的議題。隨著通道長度的縮減至奈米等級，會碰到一些無可避免的問題，例如: 貫穿效應、製程上的困難等等，長距庫倫效應影響速度過衝也是一大關鍵，為了能改善這些困擾，許多新穎的元件結構相繼被提出。在本篇論文中，我們將以電腦輔助設計軟體模擬N型雙閘極金氧半場效電晶體，通道長度小至五奈米。首先，我們用兩種載子傳輸模型，分別為Hydrodynamic模型以及Drift-Diffusion模型模擬I-V特性，並且將之與文獻中以蒙地卡羅模擬的I-V特性作比較，接著我們萃取一些參數: 臨界電壓、次臨界擺幅、DIBL、汲極/源極寄生電阻、飽和電流以及電導值。在通道長度小至五奈米的世代，飽和電流的估計將是個關鍵，模擬結果顯示，以蒙地卡羅模擬出的飽和電流，會座落在以Hydrodynamic與Drift-Diffusion模型模擬出的飽和電流之間，顯示出速度過衝之減弱。此外，以Hydrodynamic模型模擬出的飽和電流能與ITRS的高效能電流相符，以Drift-Diffusion模型模擬出的飽和電流則與ITRS的低功率電流相符。

It has been well known that how to scale the MOSFETs is a challenging issue in the recent years. With the channel lengths scaling down to nanometer dimensions, some of problems will appear in terms of punch-through, manufacturing issues, etc. Particularly, the effect of long-range Coulomb interactions on velocity overshoot is the key. In order to resolve these problems, new device architectures are proposed. In this thesis, we use TCAD (Technology Computer Aided Design) to simulate double-gate n-MOSFETs with channel length down to 5 nm. At first, we use two transport models of HD (hydrodynamic) and DD (drift-diffusion) to simulate I-V characteristics and make a comparison to Monte Carlo simulation research in the literature. Secondly, we extract the underlying parameters: threshold voltage, subthreshold swing, DIBL, source/drain parasitic series resistance, saturation drive current and transconductance. Estimating the saturation drive current Idsat is the key to the next scaling nodes (down to 5 nm). The simulation result shows that Monte Carlo Idsat lies between two models, HD and DD, indicating the weakening of velocity overshoot. In addition, simulated Idsat from both HD and DD models are comparable to ITRS high-performance and low-power ones, respectively.