FET's are inherently complex and there are many varieties which are similar in some ways, but differ in important details. My suggestion is: let's read chapter 8 some more and let's do some end of chapter problems from that chapter. Your suggestions are welcome. I am thinking of some problems related to MOSFET depletion and inversion region formation etc., numbers 8.6 to 8.9 in my version. I will scan some pages tomorrow. In the mean time, your suggestions are welcome.
P.S. Here is a warm-up problem:
1. Consider a structure that involves a metal gate, a (GaAl)As insulating layer, and undoped GaAs (in that order). Suppose the insulating region is doped with $10^{11}$ Si atoms per $cm^{2}$, so that with zero gate voltage there is a thin conducting region of areal carrier density $10^{11}$ electrons/cm^2 on the GaAs side of the interface.
a) Sketch this structure.
b) Calculate the influence of gate voltage on the carrier density at the interface. What voltage would be required to (turn off) reduce the carrier density to zero? (You can use an $\epsilon$ for (GaAl)As of about 12, or look up a value (for $Al_{0.3}$) and post it here.)
c) (What approach would make this problem not too difficult and use epsilon?)
this might be a dumb question, but where exactly is the gate voltage applied? i am picturing a battery with one terminal connected to the metal gate, and the other terminal connected to the semiconductor, but i just want to make sure that's right...
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