90 nm process paramerters, what is Wd in spice model?

[naeemmaroof]

I need process parameters to get the following:

sigma_vth = (q* tox / eox ) * sqrt (Na*Wd / (3*L*W)) ---[1]

where
tox is oxide thickness
Na is effective channel doping
Wd is the depletion region width

Now, I have 90 nm spice parameters, but I do not know which parameters represent these values. Specifically
(1) Should I use toxe or toxp (electrical or physical)
(2) Is 'ndep' what is called Na (effective channel doping)?
(3) I can not find any parameter referring to depletion region width. So what is Wd ? What is its value in generic 90nm process ?

Any help please.

Regards,
Naeem

 

[erikl]

(1) Should I use toxe or toxp (electrical or physical)
(2) Is 'ndep' what is called Na (effective channel doping)?
(3) I can not find any parameter referring to depletion region width. So what is Wd ? What is its value in generic 90nm process

(1) toxe
(2) yes. Estimate Na = 1e15 cm^-3
(3) Wd≈1µm , s. this fig. from Sze book: (Na=N_B)

 

[naeemmaroof]

thank you erikl, this book helped me