Semiconductor fundamentals: in solid-state electronics, “doping” refers to deliberately adding a very small concentration of pentavalent (donor) or trivalent (acceptor) impurity atoms into a tetravalent semiconductor lattice (such as silicon) to control carrier concentration. Validate this statement.

Introduction / Context:
Doping is the foundational technique that turns an intrinsic semiconductor into a useful electronic material by creating n-type or p-type regions. This concept underlies diodes, bipolar junction transistors, field-effect transistors, and integrated circuits. The statement claims that doping involves adding a tiny amount of pentavalent or trivalent atoms to a tetravalent host to modify conductivity.

Given Data / Assumptions:

• Host semiconductor is tetravalent (e.g., silicon, germanium), forming a covalent lattice.
• Pentavalent dopants (group V) act as donors; trivalents (group III) act as acceptors.
• Dopant concentration is small compared with host atom density (typically parts per million to parts per billion).
• Room-temperature behavior is considered for standard device operation.

Concept / Approach:
In an intrinsic lattice, each atom forms four covalent bonds. Introducing a group V dopant (such as phosphorus) contributes an extra valence electron that is weakly bound and easily ionized, yielding a free electron (n-type). Introducing a group III dopant (such as boron) creates an electron deficiency (hole) because it has only three valence electrons, forming an acceptor level that promotes hole conduction (p-type). The small quantity of dopant shifts the Fermi level and controls majority carriers without destroying the crystal structure.

Step-by-Step Solution:

Verification / Alternative check:
Device cross-sections (diodes, BJTs, MOSFETs) show engineered n/p regions formed by controlled dopant diffusion or ion implantation, directly confirming the described process.

Why Other Options Are Wrong:
Incorrect: contradicts the accepted definition of doping.

True only for germanium: also valid for silicon and many compound semiconductors.

True only for a metal lattice: metals are not doped in this semiconductor sense.

Common Pitfalls:
Confusing doping with alloying; assuming high dopant levels like alloys rather than ppm-level controlled doping; thinking dopants must be magnetic or metallic in behavior.

Final Answer:
Correct