Semiconductor doping—donor impurities: From the list {Gold, Phosphorus, Boron, Antimony, Arsenic, Indium}, identify the donor impurities for Si/Ge at room temperature.

Introduction / Context:
Donor impurities in group-IV semiconductors (Si, Ge) are typically group-V elements that contribute extra electrons to the lattice, creating n-type material. Distinguishing donors from acceptors and deep-level impurities is key for device design and process control.

Given Data / Assumptions:

• Candidates: Gold (Au), Phosphorus (P), Boron (B), Antimony (Sb), Arsenic (As), Indium (In).
• Host: Si or Ge at room temperature.

Concept / Approach:

Group-V dopants (P, As, Sb) have five valence electrons; substituting into the group-IV lattice leaves one extra electron weakly bound, acting as a donor (n-type). Group-III elements (B, In) are acceptors (p-type). Gold is not a shallow donor in Si/Ge; it introduces deep recombination levels and is often used to control lifetime, not conductivity type.

Step-by-Step Solution:

Verification / Alternative check:

Standard dopant tables list P, As, Sb as n-type dopants in Si/Ge; B, Al, Ga, In as p-type; Au introduces deep traps.

Why Other Options Are Wrong:

• Options including 1 (Au) or 3 (B) or 6 (In) misclassify acceptors/deep levels as donors.

Common Pitfalls:

• Assuming all metals (like Au) donate electrons—deep levels are not shallow donors.

Final Answer:

2, 4, 5