Question
Why is gallium arsenide (GaAs) useful for semiconductor devices operating at UHF and higher frequencies?
Answer Options
- A) Higher noise figures
- B) Higher electron mobility
- C) Lower junction voltage drop
- D) Lower transconductance
Correct Answer: B
Explanation
Gallium Arsenide (GaAs) is a III-V compound semiconductor material that has become indispensable in high-frequency applications, primarily because its physical properties allow for much faster device operation than conventional silicon. This speed advantage relates to how easily charge carriers (electrons) can move through the crystal lattice.
The key advantage of GaAs is its higher electron mobility. Electrons in GaAs can move approximately five times faster than in silicon for a given electric field strength. This superior mobility allows GaAs transistors to switch and amplify signals efficiently at Extremely High Frequencies, making it the preferred material for low-noise amplifiers (LNAs) and power amplifiers used in satellite and microwave circuits.
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