Parameter Extraction And Modeling Techniques For RF And Microwave MOSFETs

In recent ten years, advances in low-cost silicon fabrication process have resulted in deep submicron transistors with higher transit frequencies. MOSFETs have shown excellent RF and microwave performance. RFIC designers have already started to explore the use of CMOS technology in RF circuits. For reducing the design cycle time and the time-to-market, in a CAD-based design flow, the need for accurate and validated RF MOSFET models that are properly implemented in the design tools is of paramount importance. Nevertheless, the accurate modeling of RF MOSFETs is more challenging than the MOSFET modeling for digital and low-frequency analog applications. The parameter extraction and modeling techniques of RF and microwave MOSFETs are studied in this thesis. The main content of the thesis is as follows:Firstly, the modeling of the test structure of RF MOSFET up to40GHz is presented. The size of the pads and the width of interconnection lines of the test structures are analyzed and optimized based on accurate electromagnetic (EM) simulation in order to reduce the impact of the parasitics of the pad and interconnection lines. Good agreement between the measured and simulated results has been demonstrated.Secondly, a simple and efficient extraction procedure for the extrinsic gate, drain and source resistances is presented. The substrate network parameter, Csub, dependent on the drain-source (Vds) voltage is extracted in transistor cut-off region. The scaling rules of the extrinsic and intrinsic parameters are given in detail. Good agreement is obtained between the simulated and measured results for the0.13μm RF MOSFETs in the frequency range of100MHz-40GHz.Thirdly, the RF MOSFET DC behavior is characterized based on GaAs STATZ model that is a popular model that characterizes the GaAs MESFET. The parameters of STATZ model are extracted and optimized in ADS. The drain and source resistances are considered to improve the simulation accuracy. The drain and source resistances are extracted based on the equivalent circuit model of the MOSFET in the strong inversion region and Vds=0. The MOSFET DC characteristics are modeling based on GaAs STATZ model in ADS. Good agreement is obtained between the simulated and measured results. The result of experiment validates the feasibility that GaAs STATZ model is applied to model the MOSFET DC characteristics. The MOSFET DC characteristics are modeling based on BSIM3v3model. The large-signal equivalent circuit model of MOSFETs is presented. The parameters of the model are extracted from the measurement data. Good agreement is obtained between the simulated and measured results.Finally, the S-parameter measurements for model extraction and verification are made up to40GHz using the Agilent8510C network analyzer, with DC bias, which is supplied by Agilent4156A. All measurements are carried out on wafer, with using Cascade Microtech's Air-Coplanar Probes ACP50-GSG-100, with all instruments under IC-CAP software control.