对异型硅岛实现的厚膜全耗尽SOIMOSFET的模拟研究

本文提出了用异型硅岛实现的厚膜全耗尽(FD)SOI MOSFET的新结构,并分析了其性能与结构参数的关系.通过在厚膜SOI MOSFET靠近背栅的界面形成一个相反掺杂的硅岛,从而使得厚膜SOI MOSFET变成全耗尽器件.二维模拟显示,通过对异型硅岛的宽度、厚度、掺杂浓度以及在沟道中位置的分析与设计,厚膜SOI MOSFET不仅实现了全耗尽,从而克服了其固有的Kink效应,而且驱动电流也大大增加,器件速度明显提高,同时短沟性能也得到改善.模拟结果证明:优化的异型硅岛应该位于硅膜的底部中央处,整个宽度约为沟道长度的五分之三,厚度大约等于硅膜厚度的一半,掺杂浓度只要高出硅膜的掺杂浓度即可.重要的是,异型硅岛的设计允许其厚度、宽度、掺杂浓度以及位置的较大波动.可以看出,异型硅岛实现的厚膜全耗尽 SOI MOSFET 为厚膜SOI器件提供了一个更广阔的设计空间.

The Simulation Analysis of Thick Film Fully Depleted SOI MOSFET Implemented by Anti-Doped Silicon Island

A novel structure,which is implemented by anti doped silicon island to realize fully depletion in thick film SOI MOSFET,is proposed in this paper and the relationship between its performance and structure key parameters is analyzed.The thick film SOI MOSFET can be fully depleted under normal operating condition,if there is an anti doped silicon island near the back gate in the channel.Two dimensional(2 D)numerical simulations have proved that through some optimizations of the width,the height,the doping concentration and the position in the channel of the anti doped silicon island,thick film SOI MOSFET can achieve fully depleted channel which means no KINK effects,and more driving current resulting in high speed,while it suppresses the SCEs effectively.The simulation results show that:optimized anti doped silicon island should be positioned in the center of the channel near the back gate,and its width is three fifth of the channel length with height half of the thickness of silicon film,while its doping concentration keeps higher than that of the substrate.Most importantly,this novel structure shows excellent tolerance of the fluctuation of the width,height,position and doping concentration.It can be seen that this thick film FD SOI MOSFET will be one of the promising structures in design of thick film SOI MOSFET devices.