基于三维电势分布的新型围栅MOSFET研究

发布时间：2018-04-18 07:17

本文选题：CSG + MOSFET　；参考：《安徽大学》2015年硕士论文

【摘要】：近年来,由于科技的飞速发展,集成化程度越来越高。为满足集成电路发展的要求,金属氧化物半导体场效应晶体管(MOSFET, Metal-Oxide-Semiconductor Field-Effect Transistor)的特征尺寸不断减小。同时也带来一些不好的结果,严重影响MOs器件的可靠性。这对工艺技术的发展提出了更高要求,如超浅结技术、应变沟道技术等。同时出现了许多新型的三维结构,如双栅和围栅(CSG, Cylindrical Surrounding-gate)MOSFET等。其中CSG MOSFET的整个沟道被栅包围,使得栅对沟道有良好的控制力,有效抑短沟道效应。CSG MOSFET的短沟道效应提高,使晶体管尺寸得以进一步缩小。以上诸多优势使得CSG MOSFET成为扩展纳米级CMOS缩放比例的电路设计中最有前途的结构之一。本文从CSG MOSFET沟道结构设计出发,主要研究阶梯掺杂沟道(steeped SC, doping channel)CSG MOSFET.和均匀掺杂沟道CSG MOSFET的工作机制、物理模型及性能相比,分析提高MOS器件的击穿特性和抑制热载流子效应的方法。首先,使用三维仿真软件ATLAS模拟仿真SC CSG MOSFET的沟道结构特性：不同高掺杂浓度和高掺杂区域长度。详细分析不同沟道结构下SC CSG MOSFET电势、电场、Ⅰd-Ⅴds和Ⅰd-Ⅴgs等特性。接着分析栅长对SC DG MOSFET和SC CSG MOSFET两种结构的阈值电压下降和漏感应势垒降低等短沟道效应效应。结果表明,SC CSG MOSFET具有能明显减小短沟道效应和热载流子效应的影响等优点。其次,在圆柱坐标系下,建立了SC CSG MOSFET的三维体电势模型。在本文中,此模型同时计入耗尽电荷和自由电荷的影响,可以更加精确的描述开态势场。求解过程中,使用分离变量法和傅里叶逆变换法相结合,得到了SC CSG MOSFET的体电势模型。然后基于三维模型,推导了SC CSG MOSFET的阈值电压的解析模型。最后,比较了CS CSG MOSFET的建模结果和ATLAS模拟仿真结果,分析验证了模型的准确性。通过对不同沟道结构的SC CSG MOSFET电势、电场和短沟道效应进行分析,结果表明,SC CSG MOSFET改善了短沟道效应和热载流子效应,提高了击穿特性。而且SC CSG MOSFET受高掺杂浓度变化的影响比较大,漏感应势垒降低效应先增大后减小；而高掺杂区域长度对它影响比较小,但影响沟道迁移率和载流子的速度。此外通过对SC CSG MOSFET沟道结构优化进行分析,可以提高器件的可靠性。
[Abstract]:In recent years, due to the rapid development of science and technology, more and more high degree of integration. In order to meet the requirements of the development of integrated circuit, metal oxide semiconductor field effect transistor (MOSFET Metal-Oxide-Semiconductor, Field-Effect Transistor) the feature size decreases. At the same time also brought some bad results, seriously affect the reliability of the MOs device. Put forward higher requirements the development of technology, such as ultra shallow junction technology, strained channel technology. At the same time, there are many new three-dimensional structure, such as double gate and gate (CSG Cylindrical, Surrounding-gate MOSFET). The whole channel CSG MOSFET is surrounded by the gate, the gate has a good control of the channel and improve the short channel effect and effective suppression of short channel effect of the.CSG MOSFET, so that the transistor size can be further reduced. These advantages make CSG MOSFET become the extension of nano CMOS zoom One of the most promising structure circuit design. The proportion of the CSG MOSFET channel structure design of main ladder doped channel (steeped SC, doping channel) CSG MOSFET. and the working mechanism of uniformly doped channel CSG MOSFET, physical model and performance analysis, improve the breakdown characteristics of MOS devices and methods suppression of hot carrier effect. Firstly, the structure characteristic of the channel using the 3D simulation software ATLAS simulation SC CSG MOSFET: high doping concentration and high doping area length. Detailed analysis of different channel structure under the SC CSG MOSFET potential, electric field, I d- DS and d- GS V I V characteristics. Then the analysis of gate length the SC DG MOSFET and SC CSG MOSFET structure of the two kinds of threshold voltage drop and drain induced barrier lowering short channel effect. The results showed that SC CSG MOSFET can obviously reduce the short channel effect and hot carrier effect The influence of advantages. Secondly, in cylindrical coordinates, a 3D body model SC CSG MOSFET potential. In this paper, this model also included the effect of depletion charge and free charge, can more accurately describe the situation of open field. In the solving process, using the method of separation of variables and Fourier transform method. With the SC CSG MOSFET body potential model. Then based on the three-dimensional model, the analytical model of the threshold voltage of SC CSG MOSFET are derived. Finally, the modeling results of CS CSG MOSFET and the ATLAS simulation results, analysis of the accuracy of the model was verified by SC CSG. The MOSFET potential of different channel structure analysis of electric field, and the short channel effect. The results show that the SC CSG MOSFET to improve the short channel effect and hot carrier effect, improve the breakdown characteristics of CSG MOSFET and SC. The high doping concentration affected relatively large, The leakage induced barrier lowering effect first increases and then decreases, while the length of the high doped region has little effect on it, but it affects the channel mobility and carrier speed. In addition, the reliability analysis of SC CSG MOSFET channel structure can improve the reliability of the device.

【学位授予单位】：安徽大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN386

【参考文献】