How do find area of a nmos or pmos given the spice model

[Resistance]

Hi,
that was my question.. How is area occupied by the mos calculated given the spice model

regards

 

[p_shinde]

if i am rgt when u extract ur layout (this especially related to Tanner's L-Edit) u get a spice file where all ur xsistor dimensions r also extracted....


correct me if i am wrong.


thanks,
Prasad

 

[Resistance]

Hi,
I dont know abt that but am asking somethin different.
I wanna know whethet jus with a spice model in hand I can compute area of a mos or logic gate.?????
regards

 

[Ahmed Ragab]

No I don't think that's possible, because the only dimensions mentioned are the channel width and length, you don't mention any other dimensions concerning metal contacts or oxide layer or anything else.

Salam.

 

[kundan_pv]

Hi!

For calculation of Area of a MOS device ,W and L are the required parameters. A model file defines all parameters of MOS except these two. So having model file only will not help u for area calculation. U hav to specify W andd L values in ur SPICE file while including the model .

Kundan

 

[Ahmed Ragab]

Hi!

For calculation of Area of a MOS device ,W and L are the required parameters. A model file defines all parameters of MOS except these two. So having model file only will not help u for area calculation. U hav to specify W andd L values in ur SPICE file while including the model .

Kundan

Kundan,
Check any model of those in the pspice library, you will find that most of them include W & L, how come you say they're not included??
And if W & L are sufficient to calculate the area then would you kindly mention how that is done? and how can you neglect the are of drain and source with metal contacts and all?

Salam.

 

[kundan_pv]

HI Ahmed!

I m presently working with TSPICE and hav seen mosis & orbit model files. model file provides values of DEVICE CAPACITANCES,GRDING COEFFICIENT,MOBILITY and other parameters depending on the MOSFET MODEL u r going to use.( I m Using BSIM-49). u have to specify L and W according to ur technology and design respectively.


Furtther! I din't said anything like "W and L are sufficient for Area calulation". These two parameters are among those required for area calculation but not mentioned in the model file.

 

[FCMOS]

Exactly what area do you want to calculate? You want to know the area of the gate to calculate the resistance of the gate etc, or the area of the difuccion to calculated the resistance or depletion capacitance of the Source and Drain cont.

P.D The parameter for calculating the area of the difussion is in the SPICE file.
So, let me know what area do you want to calculated and i tell you what parameter you need ok.