Research And Optimization On BSIM3v3 I-V Model Of High Voltage MOSFET

With the rapid development of Very-Large-Scale-lntegrated-Circuits (VLSI), the integrity density of it is increasing and new requirements are demanded for designing and process technology of VLSI which include the High Voltage Integrated Circuits (HV IC) . HV IC is IC which integrates High Voltage Devices (HV devices) and Low Voltage Control Circuits in a single chip. Research and development of HV IC includes development of HV devices, process technology and designing. Among them the designing and simulating of HV ICs play an important role in the process of HV IC designing.With high technology developed in EDA (Electronic Design Automation) , Design automation and simulation become the necessary tool in developing process technology and theory of Semiconductor devices. They can effectively shorten the time of flow. Moreover because of the tiny expense of computers and software used for EDA compared to the equipments of IC fabrication they can diminish the cost in a great extent. However there are flaws in IC simulation. Deviations exist between simulations and actual measurements in data, especially the data of High-Voltage lightly-doped-drain MOSFET devices (HV MOSFET) . Thus the model of HV MOSFET is in need of further optimization and correction.This paper presents a new technique for modeling HV MOSFET, which is widely used in High Voltage ICs. In order to improve the BSIM3v3 SPICE MODEL in modeling HV MOSFET, I-V measurements on HV MOSFET have been made by Agilent ICCAP system. Based on the difference between HV MOSFET and Normal Low Voltage MOSFET devices (LV MOSFET), the R_d dependency of V_gs, V_ds and V_bs is discussed and the R_d and V_dsat equations in the BSIM3v3 model have been optimized. As all original parameters maintain, two parameters are led in: one is gate bias quadric coefficient of R_dsw (P_wg2) and another is gate bias coefficient of V_dsat (δ'). The optimization has been realized by modifying free SPICE and BSIM3v3 source code and compiling them into a simulator. Using ICCAP to invoke the simulator and simulate, the I-V simulated data of HV MOSFET after parameters extraction fit the measured results very well. Using this new optimized HV MOSFET BSIM3 model, High Voltage integrated circuits with HV MOSFETs can be simulated accurately.