Modelling and Analysis of Scaled MOSFET Devices and Circuit Simulation Mustafa M. El-MURADI Electronic and Electric Engineering Department Faculty of Engineering ,University of Al Fatah Tripoli, Libya Email : elmradi2005@yahoo.com MOHAMED A. ELMANSOURI Electronic and Electric Engineering Department Faculty of Engineering ,University of Al Fatah Tripoli, Libya Email : mansori82@yahoo.com Abstract—A new approach of extremely scaled MOSFET device based on modified BSIM4v6 is presented for modelling and analysis. The model ensures the continuities of current-voltage, conductance and transconductance through all voltage bias conditions. The improved model has been enhanced by device parameters and dimensions to accounts for all use in various device technologies with less extracted parameters. The accurate model has been implemented in the circuit simulation such as Ring-oscillators and CMOS circuits using HSPICE, SMART Spice and higher level SPICE, comparison with other simulation techniques showed a compromise between computation time and more complex model equations, accuracy is the major factor of simulation results and device performance. I. INTRODUCTION A new BSIM model should be synthesized to not only preserve region for specific MOS device physics but also to ensure the continuities of device characteristics such as current-voltage, and their derivatives in all terminal voltages [1]. BSIM with several different versions that have been developed and implement in SPICE simulation circuits. We present the I-V characteristics from linear to saturation region including subthreshold and strong inversion model using new modified BSIM4.6 with less numbers of parameters and compared with reported BSIM models [1-4].the model is In single expression, and ensures the continuities of the I-V, conductance and transconductance through different dimensions from voltages bs V , gs V and ds V scaled dimensions oxide thickness, channel length and width and device technology processing, physical parameters including parasitic resistance effect. During the model development parameters extraction is an important consideration with optimum numbers and values relies on the explicit use of a numerical computer optimization algorithm. To find parameters which will be best fit the computer data by interpolation with different device parameters. In this new model all precaution have been taken into considerations to come up with excellent results predicted for device characteristics compared with other published results. Following this introduction summary of model equations have been introduced in section II, section III presents the results and discussions, the circuit simulation results is introduced in section IV finally we ended by a conclusion. II. MODEL FORMULATION A major contribution of this paper to modify the model of BSIM4v6 in the parameter numbers and evaluation as well as the number of equations used to evaluate the device characteristic behaviour that has smooth transition for all regions of operation. A unified charge density model considering the charge layer thickness effect is obtained for strong inversion and subthreshold regions where used in previous BSIM models and modified. gsteff oxeff ch V C Q = 0 (1) Where oxeff C is modelled parallel capacitance ox C and DC si en x C ε = and gsteff V is the effective ( ) th gse V V − used to describe the channel charge densities from subthreshold to strong inversion .Here t v is the thermal voltage q T K B / , s Φ is the Fermi potential ( ) i D t n N v / ln 2 , off V represents the small difference between threshold voltages in strong inversion and the subthreshold regions, n is subthreshold swing parameter as it is function of bs V , channel length and interface states density, th V is the threshold voltage of the device as the current modelling of threshold voltage is important for precise description of device electric characteristics [5] . ( ) 2 2 2 1         + +         + + + = ox th gsteff B ox th gsteff bseff C A o eff T V V U T V V V U U µ µ (2) Where o µ , A U , B U and C U are extended parameters . 978-1-4244-5091-6/09/$25.00 ©2009 IEEE 475