1. The GaAs fabrication has _________ gate geometry.
A. less than one micron
B. less than two micron
C. more than one micron
D. more than two micron
Answer: A
The GaAs fabrication has characteristics such as having less than on-micron gate geometry and less than two-micron metal pitch.
2. The GaAs structure has upto _______ metal.
A. two-layer
B. three-layer
C. four-layer
D. one-layer
Answer: C
The GaAs fabrication has the feature of having four-layer metal and a four-inch diameter wafer.
3. Electron mobility of gallium arsenide is _______ that of silicon.
A. greater than
B. lesser than
C. same as
D. does not depend on
Answer: A
Electron mobility of gallium arsenide is six to seven times that of silicon resulting in very fast electron transit times.
4. Saturated drift velocity of gallium is _______ to that of silicon.
A. greater
B. lesser
C. approximately same
D. does not depend on
Answer: C
The saturated drift velocity of gallium and silicon is approximately equal. For GaAs, saturation velocity occurs at a lower threshold field than for silicon.
5. Larger energy bandgap _____ parasitic capacitances.
A. increases
B. decreases
C. maintains constant
D. does not affect
Answer: B
A large energy bandgap offers a bulk semi-insulating substrate and minimizes parasitic capacitances and allows easy electrical isolation.
6. In gallium arsenide, radiation resistance is
A. stronger
B. weaker
C. absent
D. very weak
Answer: A
In gallium arsenide radiation resistance is stronger due to the absence of gate oxide to trap charges.
7. In gallium arsenide, a wider operating temperature range is possible.
A. true
B. false
Answer: A
In gallium arsenide, a wider operating temperature range is possible due to the larger bandgap. GaAs devices are tolerant to wide temperature variations.
8. _______ can be used as light emitters.
A. forward-biased PN junction
B. reverse-biased PN junction
C. forward-biased PNP junction
D. reverse-biased PNP junction
Answer: A
The direct bandgap of GaAs allows efficient radiative recombination of electrons and holes and thus forward-biased PN junction can be used as light emitters.
9. In GaAs __________ has more intrinsic mobility.
A. electron
B. holes
C. proton
D. neutron
Answer: A
In GaAs, electrons have intrinsic mobility of 8000 cm2/V.sec whereas silicon holes have more intrinsic mobility as 500 cm2/V.sec.
10. Which has greater intrinsic resistivity?
A. silicon
B. gallium arsenide
C. gallium
D. silicon and gallium
Answer: B
Gallium arsenide has greater intrinsic resistivity of 1 × 108 ohms. cm whereas silicon has intrinsic resistivity of 2.2×105 ohm. cm.
