VD-MOSFET寄生导通电阻二维模型建模的研究

发布时间：2018-03-16 16:07

本文选题：寄生导通电阻　切入点：掺杂浓度　出处：《安徽大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着科技的迅猛发展,生活中的各个角落都有电子产品的身影,半导体元器件无疑是这些电子产品的核心,而VD-MOSFET具有驱动功率低、输入阻抗高、频率特性好、开关速度快等优良的电学性能,被广泛用于各种工业及军用系统的功率放大及控制,使其在能源控制领域至关重要的地位并至少控制开关全球50%的用电量。由于功率器件的击穿电压不能过低和过高,导通电阻过高会引起高能耗,同时所散发的热量会影响器件性能稳定。所以选择最优的VD-MOSFET结构以及掺杂浓度尤为重要。而这需要我们对VD-MOSFET器件基本原理进行全面深入的了解,建立最准确的物理模型对其特性的研究具有非常重要的意义。文献显示目前对于功率半导体导通电阻精确模型的建立依然处于缓慢发展的阶段,无论是早期的S.C.Sun近似模型还是后来利用保角变换建立近似模型,都未真正给出其导通电阻最精确的解析解。本文将针对VD-MOSFET器件的导通电阻进行深入研究,根据其电流流动特性,给出了定解问题及其半解析解法,建立了寄生导通电阻的二维模型。文章内容由以下几部分组成:首先,分析VD-MOSFET的电学特性,总结关于导通电阻的建模方法及求解过程,比较各类研究方法的优缺点。其方法主要包括解析法、数值方法以及半解析法。其次,建立VD-MOSFET导通电阻的非沟道部分的二维模型。首先依据其电阻特性将模型结构分为电子积累层、JFET区、N漂移区和衬底区;其次,分析各区域的载流子运动规律,确定其二维的状态方程和边界条件。由于VD-MOSFET各区域的掺杂浓度和导电载流子浓度有所区别,本文设定了各区域之间的衔接条件。最后利用分离变量法以及傅利叶正交变换法求出各区域电势的半解析解,最终由电势方程求得非沟道部分的寄生电阻。最后,用差分方法验证了基于半解析法的VD-MOSFET寄生导通电阻模型的电势分布和电阻,充分证明了所提出的二维模型的正确性。计算结果表明,半解析法得到的二维模型电势分布和数值计算得到的电势分布相差很小,跟据三维电势得到的等势线相差极小,整体电势状态稳定。最终比较不同参数下的半解析法模型电阻与数值计算得到的电阻值,其误差极小,基本为1%以下。本文用半解析法求解二维电势方程以及电阻方程的过程准确,对于VD-MOSFET寄生导通电阻的研究具有很高的价值。
[Abstract]:With the rapid development of science and technology, there are electronic products in every corner of life. Semiconductor components are undoubtedly the core of these electronic products, and VD-MOSFET has low driving power, high input impedance and good frequency characteristics. High switching speed and other excellent electrical properties are widely used in power amplification and control of various industrial and military systems. Make it critical in energy control and control at least 50% of the global power consumption of the switch. Because the breakdown voltage of the power device cannot be too low and too high, too high on resistance can lead to high energy consumption. At the same time, the heat emitted will affect the stability of the device. So it is very important to choose the optimal VD-MOSFET structure and doping concentration, which requires us to have a thorough understanding of the basic principles of VD-MOSFET devices. The establishment of the most accurate physical model is of great significance to the study of its characteristics. The literature shows that the establishment of the accurate model of the power semiconductor on-resistance is still in the stage of slow development. Neither the early S.C.Sun approximation model nor the conformal transformation has really given the most accurate analytical solution of its on-resistance. In this paper, the on-resistance of VD-MOSFET devices is studied in depth, according to its current flow characteristics. In this paper, the problem of definite solution and its semi-analytical solution are given, and the two-dimensional model of parasitic on-resistance is established. The content of this paper is composed of the following parts: firstly, the electrical characteristics of VD-MOSFET are analyzed, and the modeling method and solution process of on-resistance are summarized. Compare the advantages and disadvantages of all kinds of research methods. The main methods include analytical method, numerical method and semi-analytical method. Secondly, A two-dimensional model of the non-channel part of the VD-MOSFET on-resistance is established. Firstly, the model structure is divided into the N drift region and the substrate region according to its resistance characteristics. Secondly, the carrier motion in each region is analyzed. The two-dimensional equation of state and boundary conditions are determined. Due to the difference of doping concentration and conducting carrier concentration in each region of VD-MOSFET, In this paper, the connection conditions between regions are set up. Finally, the semi-analytical solution of the potential of each region is obtained by using the method of separating variables and the Fourier orthogonal transformation method, and the parasitic resistance of the non-channel part is obtained from the potential equation. Finally, The potential distribution and resistance of VD-MOSFET parasitic on-resistance model based on semi-analytical method are verified by difference method, and the correctness of the proposed two-dimensional model is fully proved. The potential distribution of the two-dimensional model obtained by the semi-analytical method and the potential distribution obtained by the numerical calculation are very small, and the difference between the potential distributions obtained by the semi-analytical method and the isopotential lines obtained by the three-dimensional potential is very small. The state of the whole potential is stable. Finally, the error between the semi-analytical model resistance of different parameters and the value of resistance obtained by numerical calculation is very small. The basic value is less than 1%. In this paper, the process of solving two-dimensional potential equation and resistance equation by semi-analytical method is accurate, which is of great value for the study of VD-MOSFET parasitic on-resistance.
【学位授予单位】：安徽大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN386

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