The GATE Grind

GATE 2015 EC – Question 19

Electronic Devices · P-N Junction and Semiconductor Devices · 1 mark · Multiple choice

A region of negative differential resistance is observed in the current voltage characteristics of a silicon PN junction if

  1. both the P-region and the N-region are heavily doped
  2. the N-region is heavily doped compared to the P-region
  3. the P-region is heavily doped compared to the N-region
  4. an intrinsic silicon region is inserted between the P-region and the N-region

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Show answer and explanation

Correct answer: (A) both the P-region and the N-region are heavily doped

Explanation

Negative differential resistance appears in a tunnel diode, which is a junction with both sides very heavily doped. Their depletion region is so thin that carriers tunnel through it.