【作者】 周蚌艳；

【导师】 柯导明； 陈军宁；

【作者基本信息】 安徽大学 ， 电路与系统， 2007， 硕士

【摘要】 随着功率集成电路飞速发展和广泛应用，功率半导体器件也取得了飞快的进步，其市场应用也逐步扩大。高压体硅LDMOS作为功率DMOS器件的一种横向高压器件非常适合应用于功率集成电路，这是因为：一方面LDMOS具有很高的击穿电压和良好的导通特性；另一方面，其栅、源和漏电极都在表面引出，从而非常容易和标准CMOS工艺相兼容，生产成本低。因此，近年来体硅LDMOS得到广泛的关注和研究。器件模型是电路仿真中不可缺少的重要元素，电路仿真结果能否正确的反映高压集成电路的电学特性，很大程度上依赖于所选取的器件模型的准确程度。由于高压LDMOS结构的多样性和复杂性，目前用于电路仿真的高压器件模型相当有限。因此建立能够用于SPICE仿真的高压器件模型成为亟待解决的问题。传统的高压器件SPICE模型是基于等效电路模型建立的，模型的准确与否很大程度上依赖于等效电路的拓扑结构，同时由于构造等效电路的标准元器件不能准确反映高压器件的特殊性，仿真的结果很难满足功率集成电路CAD设计的需要。本文在深入分析高压LDMOS器件工作原理的基础上，围绕高压LDMOS器件SPICE宏模型的建立展开研究。首先，从器件的静态特性出发，依据器件在满足一定的击穿电压的前提下，具有较低的导通电阻的要求，利用MEDICI数值模拟软件，并结合半导体理论，优化和设定了LDMOS器件的各个结构参数。其次，从器件的动态特性出发，深入分析了器件的物理工作机理，建立了高压LDMOS器件的栅源和栅漏寄生电容的物理模型，为器件的大信号、瞬态分析提供了依据。再次，在上述分析的基础之上，首次将切比雪夫多项式逼近的方法用于建立器件I-V和C-V特性的数学模型，利用数学工具MATLAB计算最优系数，从而把器件的电学行为转化为利用数学方程式表达的形式。最后，针对本文中的LDMOS器件的结构提出了新的子电路宏模型，将描述等效电路中的I-V和C-V特性的数学方程式嵌入SPICE模拟器中，解决了模型和SPICE之间的兼容问题。通过验证建立的数学模型、SPICE宏模型与MEDICI模拟之间的误差分别在5％和10％范围之内。通过以上的工作，本文最终提供了一个建立SPICE宏模型的通用方法。通过这种方法，不仅可以建立高压DMOS器件的宏模型，还可以建立其它特殊器件的宏模型，以用于集成电路CAD设计。更多还原

【Abstract】 With the rapid development and application of PICs (Power Integrated Circuits),power devices also make great progress. They are used more and more rapidly in themarket. The high voltage bulk silicon LDMOS(Lateral Double-diffused MOSFET)can be well applied in the power circuits for its good performances about thebreakdown voltage and on-resistance and its easy integration in the standard CMOSprocess flow. So many people begin to pay more attention to LDMOS in recent years.Device models are essential for circuit simulations. Whether the results ofsimulations could predict the PIC’s performance exactly, the precise HV device modelwas important and wanted. Because of the variety and complexity, at present, theamount of HV models is limited for PIC Computer Aided Design (CAD). Therefore, itis necessary and urgent to establish the SPICE modeling for PIC CAD.Conventional SPICE modeling of HV device relies on the standard of element ofequivalent circuit, the precision of simulations relies on the topological structure ofequivalent circuit. Meanwhile, because the standard element of equivalent circuit cannot reflect exactly the particularity of HV device, so the result of simulation canhardly satisfy the request of PIC CAD. This dissertation presents a methodology forSPICE macro-modeling of high-voltage LDMOS.First, according to the static characteristics of device and basic semiconductortheoretics, the optimized parameters of LDMOS were obtained with the help ofnumerical simulation software -MEDICI. Simulation results show that the designedLDMOS has a lower on-resistance while maintain high breakdown voltage. Second,considering dynamic characteristic of LDMOS, the physical operation mechanismwas analyzed and then capacitance’s physical model was proposed, which can helpfor large signal and transient device analysis. Third, the obtained I-V and C-V modelswere fitted by MATLAB using Chebyshev theory, which was the first time so far aswe know. At the end, a new equivalent circuit macro model was presented which canbe embedded in SPICE simulator. It was testified that the errors between mathematic model, SPICE macro-model and MEDICI simulation are within 5% and 10%seprately.Through these work, a universal method is formed to set up device’s SPICEmacro model. This method also can be extended to high voltage DMOS and otherspecial devices for CAD design in high voltage integrated circuits.更多还原