Analysis of Stress and Electrical Characteristics of FinFETs with Edge Dislocation Stressors

• Main Authors: Ming-Heng Tsai, 蔡明亨
• Other Authors: 劉致為
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/64484497817316115606

碩士 === 國立臺灣大學 === 光電工程學研究所 === 101 === Dislocation stressors in the source and drain build the tensile stress field in the channel of NMOSFET. An analytic model of the strain/stress field induced by the edge dislocation is presented. The model is used for stress optimization of the dislocation stressors in the NMOSFET channel. The accuracy of the model is similar to that of the finite element simulation. The closed-form solution provides a physical insight into the dislocation stressor. The analytic solution indicates that shallower dislocations generate a larger tensile stress at the edge of the channel near the virtual source. For a given dislocation depth, an optimal distance of the dislocation core from the edge is required to generate the maximum tensile stress at the channel edge. The edge dislocation stressors are also incorporated into FinFETs. A shallower dislocation induces larger stress field along the channel at top of the virtual source in the FinFET. A novel stressor, multi-edge-dislocation stressor, is proposed to induce larger stress field. Mechanisms for electrical simulations of FinFETs are carefully investigated and the accuracy of the simulation with fitted parameters is similar to the experimental data. Comparison between taper-shaped and rectangular FinFETs are studied that a rectangular FinFET has larger saturation current and better subthreshold slope than a taper-shaped FinFET does. Edge dislocations with shorter distance to the channel edge will enhancement the performance of FinFETs more. And the optimal depth of the edge dislocation is 34 nm, which is the same as the fin height.