Answer: Heavily doped semiconductor (tunneling through thin barrier).
- A A lightly doped semiconductor region at the metal interface
- B Formation of a rectifying Schottky barrier at the junction
- C Heavily doped semiconductor (tunneling through thin barrier)
- D An intrinsic, undoped semiconductor region at the contact
Correct answer: C. Heavily doped semiconductor (tunneling through thin barrier)
Explanation: Ohmic contact: formed on heavily doped semiconductor. Thin barrier allows tunneling. Resistance independent of current direction.
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.