hspice book hspice ch16 1 Thu Jul 23 19 10 43 1998 Chapter 15 Introducing MOSFET A MOSFET is defined by the MOSFET model and element parameters and two submodels selected by the CAPOP and ACM model parameters The CAPOP model parameter specifies the model for the MOSFET gate capacitances The ACM Area Calculation Method parameter selects the type of diode model to be used for the MOSFET bulk diodes Each of these submodels has associated parameters that define the characteristics of the gate capacitances and bulk diodes MOSFET models are either p channel or n channel models they are classified according to level such as Level 1 or Level 50 This chapter covers the design model and simulation aspects of MOSFET models parameters of each model level and associated equations MOSFET diode and MOSFET capacitor model parameters and equations are also described For information about individual models and their parameters refer to Chapter 16 Selecting a MOSFET Model The following topics are covered in this chapter Understanding MOSFET Models Selecting Models Using Nonplanar and Planar Technologies Using a MOSFET Diode Model Using MOS Diode Equations Using Common Threshold Voltage Equations Performing MOSFET Impact Ionization Using Noise Models Using Temperature Parameters and Equations Star Hspice Manual Release 1998 2 15 1 hspice book hspice ch16 2 Thu Jul 23 19 10 43 1998 Understanding MOSFET Models Introducing MOSFET Understanding MOSFET Models The selection of the MOSFET model type for use in analysis usually depends on the electrical parameters critical to the application Level 1 models are most often used for simulation of large digital circuits where detailed analog models are not needed Level 1 models offer low simulation time and a relatively high level of accuracy with regard to timing calculations When precision is required as for analog data acquisition circuitry more detailed models such as the Level 6 IDS model or one of the BSIM models Level 13 39 or 49 can be used For precision modeling of integrated circuits the BSIM models take into account the variation of model parameters as a function of sensitivity of the geometric parameters The BSIM models also reference a MOS charge conservation model for precision modeling of MOS capacitor effects Use the SOSFET model Level 27 to model silicon on sapphire MOS devices You can include photocurrent effects at this level Use Levels 5 and Level 38 for depletion MOS devices Level 2 models take into account bulk charge effects on current Level 3 models require less simulation time and provides as much accuracy as Level 2 and have a greater tendency to converge Level 6 models are compatible with models originally developed with ASPEC Level 6 can be used to model ion implanted devices 15 2 Star Hspice Manual Release 1998 2 hspice book hspice ch16 3 Thu Jul 23 19 10 43 1998 Introducing MOSFET Selecting Models Selecting Models A MOS transistor is described by use of an element statement and a MODEL statement The element statement defines the connectivity of the transistor and references the MODEL statement The MODEL statement specifies either an n or p channel device the level of the model and a number of user selectable model parameters Example M3 3 2 1 0 PCH parameters MODEL PCH PMOS LEVEL 13 parameters The above example specifies a PMOS MOSFET with a model reference name PCH The transistor is modeled using the Level 13 BSIM model The parameters are selected from the model parameter lists in this chapter MOSFET Model Levels MOSFET models consist of client private and public models selected by the parameter MODEL statement LEVEL parameter New models are constantly being added to HSPICE Not all MOSFET models are available in the PC version of HSPICE Table 151 shows what is available for PC users Models listed are either on all platforms including PC as indicated in the third column or they are available on all platforms except the PC as indicated in the last column Level MOSFET Model Description All Platforms including PC 1 Schichman Hodges model X 2 MOS2 Grove Frohman model SPICE 2G X 3 MOS3 empirical model SPICE 2G X 4 Grove Frohman Level 2 model derived from SPICE 2E 3 X Star Hspice Manual Release 1998 2 All Platforms except PC 15 3 hspice book hspice ch16 4 Thu Jul 23 19 10 43 1998 Selecting Models Introducing MOSFET All Platforms including PC All Platforms except PC Level MOSFET Model Description 5 AMI ASPEC depletion and enhancement TaylorHuang X 6 Lattin Jenkins Grove ASPEC style parasitics X 7 Lattin Jenkins Grove SPICE style parasitics X 8 advanced Level 2 model X 9 AMD X 10 AMD X 11 Fluke Mosaid model X 12 CASMOS model GTE style X 13 BSIM model 14 Siemens Level 4 X 15 user defined model based on Level 3 X 16 not used 17 Cypress model X 18 Sierra 1 X 19 Dallas Semiconductor model X 20 GE CRD FRANZ X 21 STC ITT X 22 CASMOS GEC style X 23 Siliconix X 24 GE Intersil advanced X 25 CASMOS Rutherford X 26 Sierra 2 X 15 4 X Star Hspice Manual Release 1998 2 hspice book hspice ch16 5 Thu Jul 23 19 10 43 1998 Introducing MOSFET Selecting Models All Platforms including PC All Platforms except PC Level MOSFET Model Description 27 SOSFET 28 BSIM derivative Meta software proprietary model X 29 not used 30 VTI X 31 Motorola X 32 AMD X 33 National Semiconductor X 34 EPFL not used X 35 Siemens X 36 Sharp X 37 TI X 38 IDS Cypress depletion model X 39 BSIM2 X 46 SGS Thomson MOS Level 3 X 47 BSIM3 Version 2 0 X 49 BSIM3 Version 3 50 Philips MOS9 X not officially released equations are proprietary no documentation will be provided requires a license and equations are proprietary no documentation will be provided MOSFET Capacitor Selection The MOSFET capacitance model parameter CAPOP is associated with the MOS model Depending on the value of CAPOP different capacitor models are used to model the MOS gate capacitance that is the gate to drain capacitance Star Hspice Manual Release 1998 2 15 5 hspice book hspice ch16 6 Thu Jul 23 19 10 43 1998 Selecting Models Introducing MOSFET the gate to source capacitance and the gate to bulk capacitance CAPOP allows for the selection of several versions of the Meyer and charge conservation model Some of the capacitor models are tied to specific DC models they are stated as such Others are for general use by any DC model CAPOP 0 SPICE original Meyer model general CAPOP 1 modified Meyer model general CAPOP 2 parameterized modified Meyer model general default CAPOP 3 parameterized Modified Meyer model with Simpson
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