SEMICONDUCTOR

Assume the valence electron is removed from a copper atom. The net charge of the atom because:

• 0

• +1

• -1

• +4

Suppose there is an atom of oxygen, containing eight protons and eight neutrons in the nucleus, and four neutrons are added to the nucleus. The resulting atomic weight is about:

• 16

• 18

• 20

• 24

At absolute zero temperature an intrinsic semiconductor has:

• a few electrons

• Many holes

• Many free electrons

• no holes or free electrons

An intrinsic semiconductor has some holes in it at room temperature. What causes these holes?

• Doping

• Free electrons

• Thermal energy

• Valence electrons

Each atom in a silicon crystal has

• four valence electrons

• four conduction electrons

• eight valence electrons, four of its own and four shared

• no valence electrons because all are shared with other atoms

As the forward current through a silicon diode increases, the voltage across the diode:

• increases to a 0.7 V maximum

• decreases

• is relatively constant

• decreases and then increases

A silicon diode has a saturation current of 5nA at 25°C. What is the saturation current at 88°C?

• 392nA

• 370nA

• 640nA

• 650nA

If a surface leakage current is 4nA for a reverse voltage of 35V, what is the surface leakage current for a reverse voltage of 43V?

• 2.8nA

• 3.3nA

• 4.9nA

• 8nA

Determine the bulk resistance of a diode for a forward voltage of 0.93V at 1 ampere. (Assume Si diode is used)

• 0.23Ω

• 0.53Ω

• 0.73Ω

• 0.93Ω

Which capacitance dominates in the reverse-bias region?

• depletion

• conversion

• diffusion

• None of the above