How to calculate uo * Cox for 50nm Technology

[anjankumarkn]

Hi,
How do we find µn * Cox for nmos transistor by hand calculation and by operating point analysis in Cadence(Print DC operating points)?

With Diode connected mosfet and drain connected to a current source, I get µn * Cox = 223u
With gate and drain connected to a voltage source, I get µn * Cox = 85u.
Please let me know which procedure is correct or is there any other procedure to get µn * Cox.

The model file is below:

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[erikl]

For hand calculation: Use the equation

Cox = ε_SiO2 / tox

... where ε_SiO2 = 34.5 fF/(µm)² and tox = toxe (s. line 6 of your model file) . For the above equation, use the toxe value (given in units of [m]) in [nm], i.e. for your 50nm process Cox = 34.5/1.4 ≈ 25 fF/(µm)².

For the transconductance factor k = µn * Cox calculation, for µn use the low field mobility u0 values from your model file (s. lines 19 resp. 78 of your model file, different values for nmos & pmos), given in [m²/V*s] units.

From operating point analysis use the Ids value and calculate the transconductance factor k = µn * Cox from the equation given here.