Research Of SiGe HBT Small-Signal Modeling

With the rapid development of4G mobile communications and Internet of things technology, people’s demand for high-performance devices and circuits are also growing rapidly, during people’s continuously exploration and development of new material and new devices, Heterojunction Bipolar Transistor (HBT) device which employs SiGe process owns high integration, low cost, high compatibility with traditional CMOS process and many other advantages, which is far more superior than the traditional Bipolar Junction Transistor (BJT) and groups Ⅲ and Ⅴ components. In the area of monolithic microwave integrated circuits (MMIC) operating, satellite communication, mobile terminals, radar systems, and the fourth generation of mobile communication, etc, SiGe HBT has showed broad application prospect. An accurate model is of vital importance in circuit and device designing, Therefore the research of SiGe HBT technology has become the focus of the study hotspot.This paper is to explore the fast HBT modeling method which based on the device simulation software TCAD and circuit simulation software, The main research content is as follows:The basic features and growth techniques of SiGe materials are presented first, the basic principle of HBT is explained explicitly, and the equivalent circuits and their features of the current popular model are then introduced, then the hybrid-π model is chosen as the basic model. Then the meaning of the various parameters and the corresponding calculation formula of small signal π type equivalent circuit are explained explicitly.The device to be measured is token from Sentaurus TCAD template device, according to the device structure size information and doping concentration information etc, the initial value of model parameters and the parameter optimization range are determined. Put the obtained initial value into small signal equivalent circuit, executing ADS S parameter simulation, compare the simulation results with that of TCAD. Then using the parameter optimization function of ADS to fitting the simulation curve to the measured one in the given parameter optimization range. Add extrinsic circuit parameters to the equivalent circuit, execute simulation and optimization as above and check the influence of extrinsic model parameters to the accuracy of model. Generally speaking, The modeling method connects the process and physical parameters of the underlying device with the upper device performance expressed by S parameter, it can set up small signal equivalent circuit model of the device very quickly, and it has good guidance value for the design of device structure and high frequency application circuit.