Methods of predicting unity gain frequency with direct current and/or low frequency parameters

1. A method of predicting a unity gain frequency (f T ) in a metal-oxide-semiconductor field-effect transistor (MOSFET) device in a manufacturing line, the method comprising:

measuring a first set of in-line direct current (DC) parameters of the MOSFET on the manufacturing line at a first drain voltage (V d1 ), wherein the first drain voltage is a range of drain voltages selected to be representative of a range of drain voltages expected in the MOSFET;

extracting a transconductance (G m ) from the first set of in-line DC parameters as a function of a gate-voltage (V g ) and the first drain-voltage (V d1 );

measuring a second set of in-line DC parameters of the MOSFET on the manufacturing line at a second drain voltage (V d2 ), wherein the second drain voltage is equal to approximately zero;

extracting a total gate capacitance (C gg ) from the second set of in-line DC parameters as a function of the gate-voltage (V g ); and

predicting the unity gain frequency (f T ) of the MOSFET based upon the extracted transconductance (G m ) and the extracted total gate capacitance (C gg ).

2. The method of claim 1 , wherein the first set of in-line DC parameters includes a drain-current gate-voltage (I d V g ) characteristic.

3. The method of claim 1 , wherein the second set of in-line DC parameters includes a total gate capacitance gate-voltage (C gg V g ) characteristic.

4. The method of claim 1 , wherein the MOSFET includes a multi-finger MOSFET having a channel width larger than a channel length, with a perimeter defined along a drain.

5. The method of claim 1 , wherein the unity gain frequency (f T ) is calculated according to the equation:

f

T

=

G

m

2

*

π

*

C

gg

.