Assignment

Silicon is doped with a group III element. The minority carrier concentration is 10⁷/cm The concentration of majority carriers electrons/holes (circle one) is /cm³ and the doping concentration N_A or N_D (circle one) is approximately /cm³

A semiconductor might have n_{i ˜} 10¹⁰/cm³ For an insulator n_{i ˜} _____/cm³

What can we change to increase conductivity if n (or p) is fixed?

Write the expression for Capacitance of a parallel plate capacitor:

The PN junction sketched in Figure 1 has 22pF capacitance at 4v reverse bias. We might expect 11pF at a reverse bias of about ____ v.

We increase N_A in Figure 1 by 10 without any other changes. The new capacitance at 4v reverse bias is expected to be about _____ pF.

One side of a PN junction is doped with 10¹⁵/cm³Al. Chose an element _____ and concentration _____/cm³ that results in a depletion zone as sketched in figure 1. For a symmetrical depletion zone, increase/decrease (circle one) the added element concentration to ____/cm³

A zener diode has breakdown voltage 3.2 volts. To increase the breakdown voltage to 4.5 volts, we should increase/decrease (circle one) the doping levels.

Write the expression below for the current through a forward biased PN diode.

The value of kT/q at room temperature ______ v. What is a typical value for the ideality factor n in the diode current expression, based on your lab measurements n_˜ ______.

The output of a half wave rectifier power supply is shown in figure _____ and the output of a full wave rectifier power supply is shown in figure _____ . The variation in output voltage is called "ripple." If ripple is too large, we may reduce it with more ______.