To cope with the continuous evolution of VLSI technology, many short-channel MOSFET I-V models for circuit simulation have been developed. Most of these models, however, are either not adequately covering the small-size effects that become significant at the deep-submicron level, or are highly empirical. Empirical models can have the advantages of easy formulation, because of the use of a large number of empirical parameters. They may provide good accuracy in fitting a single device from a wide range of technologies. However, their drawbacks are many: generating size-independent process files is a very difficult task. Extrapolating a process file for a present technology to a future one is virtually impossible, and, perhaps most important, circuit designers may lose the intuition which is vital in achieving high performance analog and digital circuits. BSIM3 is developed to address these drawbacks.
BSIM3 is a physical model with extensive built-in dependencies of important dimensional and processing parameters such as channel length (L), width (W), gate oxide thickness junction depth, , substrate doping concentration, and LDD structures, and so forth. It allows users to accurately model, upon parameter extraction on existing technology, or predict, based on the default or extracted technologies, MOSFET behavior over a wide range of existing and future technologies. Using a coherent pseudo 2D formulation, such major short-channel effects and high field effects as threshold voltage reduction, non-uniform doping effect, mobility reduction due to vertical field , carrier velocity saturation, channel-length modulation (CLM), drain induced barrier lowering (DIBL), substrate current-induced body effect (SCBE), subthreshold conduction, parasitic resistance effect, and LDD effect are properly included. Meticulous care has been taken to retain the physical functional forms while improving model accuracy and computational efficiency. The model is compact, and time-consuming functions are excluded. The ease of parameter extraction was also a major consideration. The number of parameters is small (~ 28) and every parameter has a physical meaning; the effects of parameters on output characteristics are very predictive. This feature of BSIM3 makes statistical study of the device fabrication process possible. Drain current and its first order derivative in all operation regions are continuous, which removes all kinks and glitches at the boundaries between the regions. BSIM3 has been implemented into SPICE3 and the divergence problem has been greatly improved.
Documentation Included with the Program:
- SPICE3E User's Guide and Installation Notes.
- BSIM3 User's Manual. Available separately for $10.00
- BSIM3 Parameter Extraction User's Guide. Available separately for $1.00
Additional Documentation Available:
- J. H. Huang, Z. H. Lui, M. C. Jeng, P. K. Ko, and C. Hu, A Physical Model for MOSFET Output Resistance (UCB/ERL M93/56, December 1992). $2.50
- J. H. Huang, Z. H. Lui, M. C. Jeng, P. K. Ko, and C. Hu, A Robust Physical and Predictive Model for Deep-Submicrometer MOS Circuit Simulation (UCB/ERL M93/57, May 1993). $2.50
Foreign Distribution: Yes