432 CHAPTER 8. FIELD EFFECT TRANSISTORS
Problem 8.5Consider the device in problem 8.4. Calculate the maximum channel
thickness at which the device is OFF when no gate bias is applied, i.e., the device is an
enhancement MESFET.
Problem 8.6Consider a GaAs MESFET with the following parameters:
Schottky barrier height =0.8V
Channel doping =10^17 cm−^3
Channel depth =0. 06 μm
Calculate the gate bias needed to open up the MESFET channel.
Problem 8.7Consider a GaAs MESFET with the following parameters:
Channel mobility, μn = 6000 cm^2 /V·s
Schottky barrier height, φb =0.8V
Channel depth, h =0. 25 μm
Channel doping, Nd =5× 1016 cm−^3
Channel length, L =2. 0 μm
Gate width, Z =25μm
Calculate the 300 K saturation current when a gate bias of 0.0 V and−1.0 V is applied to
the MESFET. Also calculate the transconductance of the device at these biases.
8.12FURTHERREADING ...............................
- General
- D. A. Neaman,SemiconductorPhysicsandDevices (Irwin, Boston, MA, 1997).
- R. F. Pierret,FieldEffectDevices (Vol. 4 of the Modular Series on Solid State
Devices, Addison-Wesley, Reading, MA, 1990).
- M. Shur,PhysicsofSemiconductorDevices (Prentice-Hall, Englewood Cliffs, NJ,
1990).
- S. M. Sze,PhysicsofSemiconductorDevices (Wiley, New York, 1981).
