P-N Junction
Shockley equation, depletion region, I-V characteristic
Parameters
1. What happens to the built-in voltage Vbi of a p-n junction if dopant concentrations Na and Nd are multiplied by 10?
A. It becomes 10 times larger
B. Increases by ~0.06V (ln(10)·Vₜ)
C. It decreases
D. Does not change
2. Si p-n junction at 300K. Temperature rises to 600K. By approximately how many times does saturation current J₀ increase? (ni ≈ 10¹⁰→10¹⁵ cm⁻³)
A. ~10×
B. ~100×
C. ~10⁵×
D. ~10¹⁰×
3. Na = 10¹⁸ cm⁻³, Nd = 10¹⁵ cm⁻³ (asymmetric junction). In which side does the depletion region mainly extend?
A. Into the p-side
B. Into the n-side
C. Equally into both sides
4. Why does power electronics use GaN and SiC instead of Si?
A. Large Eg → high temp., high voltage, lower losses
B. Low J₀ → less current
C. Cheaper to manufacture
D. Higher mobility