Physics Electronics PMDC Conceptual Practice
PMDC Verified Question 307 of 494
Why are N-type semiconductor channels preferred over P-type channels in high-speed electronic switching devices?
A
Electrons have higher mobility than holes, allowing faster transit times and higher frequency operation
B
N-type materials contain no atomic nuclei
C
P-type materials cannot be manufactured in silicon
D
Electrons carry positive charge in N-type semiconductors
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Electrons have higher mobility than holes, allowing faster transit times and higher frequency operation
Concept:

Because electron mobility is roughly 2.5 to 3 times higher than hole mobility (\( \mu_n > \mu_p \)), N-channel devices achieve lower on-resistance and faster carrier transit times (\( \tau = L / v = L / (\mu E) \)).

Formula:

$$\tau_{\text{transit}} = \frac{L^2}{\mu V} \implies \text{Higher } \mu_n \implies \text{Shorter Transit Time } \tau \implies \text{Faster Switching}$$

Solution:

  • Higher electron mobility (\( \mu_n \)) allows carriers to drift faster under an applied electric field.


  • This reduces transit times through device channels, enabling higher switching speeds and better high-frequency performance.


Why other options are incorrect:

  • Option B: All semiconductor materials contain atomic nuclei.
  • Option C: P-type silicon is widely manufactured and used across the semiconductor industry.
  • Option D: Electrons always carry a negative charge of \( -1.6 \times 10^{-19}\text{ C} \).

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