Electronic Devices Laboratory mtinker@utdallas.edu CE/EE 3110

Metal Oxide Semiconductor

Field Effect Transistors

Metal Oxide Semiconductor FETs

Electronic Devices Laboratory mtinker@utdallas.edu CE/EE 3110

• MOSFET device can be characterized in a large variety of ways

IDS versus VDS

IDS1/2 versus VGS with gate to drain shorted to drain power supply

Channel conductance gDS in linear region versus VGS

Channel resistance rd in saturation region versus VDS at different VGS

Transconductance gm in linear and saturation regions versus VGS at different VDS

Metal Oxide Semiconductor FETs

Electronic Devices Laboratory mtinker@utdallas.edu CE/EE 3110

IDS versus VDS for an n-channel MOSFET (left) and IDS1/2 versus VGS and its

corresponding slope with VGS = VDS causing transistor to go into saturation (right).

Metal Oxide Semiconductor FETs

Yields linear relation between IDS1/2 and VGS – VT

Slope =

Electronic Devices Laboratory mtinker@utdallas.edu CE/EE 3110

Channel conductance gDS versus VGS in linear region for VDS = 0.050 V (left) and

channel resistance rd versus VDS in saturation region for several values of VGS (right).

Metal Oxide Semiconductor FETs

Channel resistance rd equals slope of IDS versus

VDS in saturation region

Electronic Devices Laboratory mtinker@utdallas.edu CE/EE 3110

Transconductance gm versus VGS at various VDS in linear and saturation

regions (left) and low-frequency small-signal model of the MOSFET (right).

Metal Oxide Semiconductor FETs

Linear region

Saturation region

Electronic Devices Laboratory mtinker@utdallas.edu CE/EE 3110

Metal Oxide Semiconductor FETs

LabView program used to generate IDS versus VDS for VGS

ranging from 0 to 5V in 0.5 V steps

Electronic Devices Laboratory mtinker@utdallas.edu CE/EE 3110

Metal Oxide Semiconductor FETs

LabView data generated for IDS versus VDS for VGS ranging from 0 to

5V in 0.5 V steps; determine the pinch-off locus from the acquired data

Electronic Devices Laboratory mtinker@utdallas.edu CE/EE 3110

Metal Oxide Semiconductor FETs

LabView program used to generate gDS versus VGS for

VDS = 100 mV in linear region

Electronic Devices Laboratory mtinker@utdallas.edu CE/EE 3110

Metal Oxide Semiconductor FETs

LabView data generated for gDS versus VGS for VDS = 100 mV in linear

region; determine both VT and µnZCi/2L from the acquired data

Electronic Devices Laboratory mtinker@utdallas.edu CE/EE 3110

Metal Oxide Semiconductor FETs

LabView program used to generate rD versus VDS at

VGS = 2.5, 3.0, 3.5, 4.0, 4.5, and 5.0 V

Electronic Devices Laboratory mtinker@utdallas.edu CE/EE 3110

Metal Oxide Semiconductor FETs

LabView data generated for rD versus VDS at VGS = 2.5, 3.0, 3.5, 4.0, 4.5,

and 5.0 V (left) and calculated values from IDS-VDS characteristics (right)

Electronic Devices Laboratory mtinker@utdallas.edu CE/EE 3110

Metal Oxide Semiconductor FETs

LabView program used to generate gm versus VGS

at VDS = 1.0 V, 3.0 V, and 5.0 V

Electronic Devices Laboratory mtinker@utdallas.edu CE/EE 3110

Metal Oxide Semiconductor FETs

Labview data generated for gm versus VGS at VDS = 1.0 V, 3.0 V, and 5.0 V

and used to determine both VT and µnZCi/2L from the acquired data (left)

and calculated values from IDS-VDS characteristics (right)

Electronic Devices Laboratory mtinker@utdallas.edu CE/EE 3110

Metal Oxide Semiconductor FETs

LabView program used to generate ID(sat) versus VDS when VDS = VGS

causing transistor to go into saturation

Electronic Devices Laboratory mtinker@utdallas.edu CE/EE 3110

Metal Oxide Semiconductor FETs

LabView data generated for ID(sat) (left) and ID(sat)1/2 (right) versus VGS

when VDS = VGS causing transistor to go into saturation used to

determine both VT and µnZCi/2L from the acquired data