Answer: Drain depletion charge extends under channel, reducing effective Vth (drain-induced barrier lowering, DIBL).
- A The gate oxide layer becomes progressively thicker as the channel length is shortened according to standard textbooks
- B Drain depletion charge extends under channel, reducing effective Vth (drain-induced barrier lowering, DIBL)
- C The gate dielectric layer undergoes a sudden catastrophic electrical breakdown event in general practice
- D The substrate doping concentration increases sharply near the shortened channel region as frequently described
Correct answer: B. Drain depletion charge extends under channel, reducing effective Vth (drain-induced barrier lowering, DIBL)
Explanation: Short channel effects: drain depletion region reduces barrier for channel formation. Vth decreases as channel length shrinks. DIBL causes V<sub>th</sub> to decrease with V<sub>DS</sub>.
Conductors have overlapping bands, semiconductors have a small energy gap that can be bridged by heat or doping, and insulators have a large gap that blocks conduction.
Concept context
Band theory, p-n junction, diodes, transistors, logic gates, and integrated circuits.