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Hello,
I am designing and simulating an analog circuit using 45nm nmos,pmos . I am using model files from :http://ptm.asu.edu/modelcard/45nm_MGK.pm.
I need the mobility and Cox (gate oxide capacitance per unit area) values for designing of circuit.Can anyone help me how to
know,calculate the mobility and Cox values from model files.
The PTM bullk planar models at ASU are based on BSIM4. Check the BSIM4 model manual to check for the mobility parameter in the models. It should be a parameter called u0 (check the manual for units). You can get the equivalent oxide thickness from the models and calculate Cox. However, a better method would be to use HSPICE to get the Cgate value. Check Chapter 7: MOSFET Capacitance Model in the HSPICE Reference Manual: MOSFET Models for detailed instructions on how to do that. Let me know if you have any more questions, I am one of the contributors to the new PTM-MG (FinFET) models.
Hi,
Thank you very much for the reply.Can you please explain the difference between the following two model files .i.e b/w PTM model and BSIM4 model .I am new to these .
BSIM4 stands for Berkeley Short-Channel IGFET Model 4 (ver 4). These are a set of analytical equations used to model short channel MOSFETs (bulk planar). It tries to capture most of the transistor device physics and uses a large number of device parameters that can be modified to 'fit' to real devices. So foundries measure experimental devices and try to 'match' the I-V and C-V curves by changing these BSIM4 parameters. The set of parameters that 'fit' a 45nm device is called the a 45nm transistor file. These can be used for circuit simulation in simulators such as HSPICE because HSPICE has all the BSIM4 model equations 'coded' into their simulator.
Since most of the transistor technology model files are proprietary, the PTM project was started to 'predict' the transistor model parameters for a particular generation. More details of the model parameter derivation can be found in the following paper: W. Zhao, Y. Cao, "New generation of Predictive Technology Model for sub-45nm early design exploration," IEEE Transactions on Electron Devices, vol. 53, no. 11, pp. 2816-2823, November 2006.
In short, the PTM model file is a list of BSIM4 parameters that describes the transistor of a particular technology generation (45nm/32nm etc.). Hope that answers your question, let me know if you need more details.
