Measurement on Ids-Vds graph.

[phongphanp]

How to estimate the values of kn,vT , λn, γ from characteristic curves?

 

[wylee]

From the Ids-Vds graph you have plotted, λ can be estimated through
Ro = delta(Vds)/delta(Ids) = 1/(λxIds)

Ro is first measured from the slope of delta(Vds)/delta(Ids) at the saturation region part of the curve

After you found Ro, pick a Ids value you interested at the saturation region part of the curve and find λ using the formula Ro = 1/(λxIds)

 

[phongphanp]

How about Bulk-threshold parameter ,γ .
The region in red circle in below img related with γ?

http://www.geocities.com/phongphanp/p.bmp

 

[noiseless]

No. the region in red circle is not related to Y. I don't know what process it is, so i cannot tell you what may be the reason

 

[phongphanp]

I use AMS 0.35um CMOS process. and now I think that the line in red one be mirage because spice use error model (found in IEEE paper) but when run vgs value from 0 to 8 Volts in anather model, the mirage line disappear in image . when continous simulated to 12 up, the concave line ON again!
How we will find lamda value? ,(By simple method but have good accuracy ). Need source or else.
thank ,
phongphanp@yahoo.com.

 

[Karthikeya]

hi

concave line the graph is the breakdown region of mosfet. this region of operation must be avioded. i don't understand why the breakdown region is near 5v for 0.35u process ...it must 0.5u process i guess!!! for 0.35u it occurs near 3.3v.
to find lambda u can take the ratio of slope of the curve in sat region and Id value in middle of curve. if u r using cadence then find the gds value and divide by Id. similarly find betaeff in cal and divide by w/l ratio to find kn'

regards