Methods of predicting unity gain frequency with direct current and/or low frequency parameters
Various embodiments include approaches for predicting unity gain frequency in a MOSFET. In some cases, a method includes predicting a unity gain frequency (f T ) in a MOSFET device in a manufacturing line, the method including: 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 ); 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 ); 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 ).
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 );
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 (V d2 ) is distinct from the first drain-voltage (V d1 );
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 ),
wherein the unity gain frequency (f T ) is calculated according to the equation:
f
T
=
G
m
2
*
π
*
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 second drain voltage is equal to approximately zero.
5. 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.
6. 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 );
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 (V d2 ) is distinct from the first drain-voltage (V d1 );
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 ).
7. The method of claim 6 , wherein the second drain voltage is equal to approximately zero.