HiSIM
Surface Potential-Based MOSFET Model

An Advanced Innovative CMOS Model

HiSIM is developed at Hiroshima University, in collaboration with the STARC research center.
This model employs the drift-diffusion approximation, correctly modeling the surface potential in the channel.

Conventional MOSFET models often use unphysical parameters to smooth characteristics between the different operation modes. Since HiSIM needs only one set of equations, valid over all modes of operation, only physical parameters are necessary.

Therefore, HiSIM is not only accurate, but it also reduces the number of parameters needed to model a MOSFET device.

The HiSIM approach results in :

• No interdependence of major parameters
• Easy parameter extraction
• Only 19 parameters needed to model a I-V characteristic
• Derivatives are continuous over the whole operating range
• One parameter set for all channel lengths and widths
  

Physical Effects

HiSIM accounts for the following effects:

Gate intrinsic capacitance vs VGS

Surface potentials vs VGS

ID=f(VD) characteristic

Circuit Simulation Examples

HiSIM demonstrates high accuracy (better than BSIM4) and at the same time very high simulation speed. It is a very general purpose model and suitable for accurate analog and in particular also very large circuit simulations (well over 1 million transistors). Its convergence properties are by far the best compared to any other commercial CMOS model.

Key Properties

• Applicable for state of the art device geometries.
• Efficient operating point calculation for fast simulation times, while maintaining high accuracy.
• Unified description for all bias conditions
• MOS intrinsic capacitance calculated directly from charges in model
• No specific parameters for capacitances of MOSFET as with earlier models
• Complete operation from one set of equations rather than independent equation for different operating bias conditions
• Binning option to model new physical effects not yet accounted for in the model equations

Example 1: HiSIM simulation shows good accuracy

Example 2: DAC 90nm circuit functionality.

Example 3: 2k RAM circuit.

Simucad Implementation

• HiSIM is compatible with VZERO and BYPASS options in order to achieve great speed performance
• HiSIM is ready to be used on parallel computer architectures
• Internal warnings and diagnostics provide valuable information to help find convergence issues
• Device internal variables (currents, conductances, charges...) can easily be accessed like any other parameter
• HiSIM model is part of the ModelLib product-independent model library
  

Rev. 101807_04