Device physics – which device uses a metal–silicon junction as its principle? Identify the semiconductor device that relies on a metal–silicon (Schottky) junction for its operation.

Introduction / Context:
Semiconductor junctions determine device behavior. P–N junctions dominate traditional diodes and SCRs, while metal–semiconductor junctions form Schottky barriers with distinctive electrical traits (low forward drop and fast switching).

Given Data / Assumptions:

• Metal–silicon junction creates a Schottky barrier.
• Comparing typical power devices.

Concept / Approach:

Schottky diodes use a metal contact on N-type silicon, forming a rectifying barrier. No minority-carrier charge storage exists, enabling very fast recovery and low Vf, at the expense of higher reverse leakage and lower reverse voltage ratings than P–N diodes.

Step-by-Step Solution:

Verification / Alternative check:

Datasheets specify “Schottky barrier” and show low stored charge and negligible reverse recovery.

Why Other Options Are Wrong:

• General-purpose power diode: P–N junction.
• SCR: multiple P–N layers (pnpn).
• MOSFET: insulated gate; body diode is P–N, not metal–silicon rectification.

Common Pitfalls:

Confusing the MOSFET’s metal gate with a rectifying junction; the gate is insulated by SiO2 and does not form a conduction junction to silicon.

Final Answer:

Schottky diode