Difficulty: Easy
Correct Answer: arsenic
Explanation:
Introduction / Context:
Doping tailors semiconductor conductivity by adding controlled impurities. Pentavalent dopants (Group V) donate extra electrons and produce n-type material. Recognizing common dopants is essential for understanding device fabrication and the electrical behavior of junctions.
Given Data / Assumptions:
Concept / Approach:
Pentavalent atoms such as phosphorus (P), arsenic (As), and antimony (Sb) have five valence electrons. When substituted into a silicon lattice (valence 4), one electron remains weakly bound and can be easily promoted to conduction, yielding an electron-rich (n-type) semiconductor. Trivalent dopants (Group III) like boron (B) and gallium (Ga) create p-type material by accepting electrons (creating holes).
Step-by-Step Solution:
Verification / Alternative check:
Standard semiconductor texts and process notes list P, As, Sb as donor species. As is common in diffusion and ion implantation steps for forming shallow, well-controlled junctions.
Why Other Options Are Wrong:
Common Pitfalls:
Confusing donors and acceptors due to periodic table position. Remember: Group V → n-type; Group III → p-type.
Final Answer:
arsenic
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