The impurity atoms needed to make a p-type semiconductor are

Options

A. phosphorus
B. boron
C. antimony
D. arsenic

Answer

To determine the impurity atoms needed to make a p-type semiconductor, we need to understand the concept of p-type semiconductors and the types of impurities used in their formation.

### Step-by-Step Solution:

1. **Understanding p-type Semiconductors**:
- A p-type semiconductor is formed when a trivalent impurity is added to a semiconductor material like silicon (Si) or germanium (Ge).

2. **Characteristics of Trivalent Impurities**:
- Trivalent impurities have three valence electrons. When these atoms are introduced into the silicon or germanium crystal lattice, they replace one of the silicon or germanium atoms.

3. **Formation of Holes**:
- The three valence electrons of the trivalent atom form covalent bonds with the neighboring silicon atoms. However, since there is one missing electron (the trivalent atom has only three electrons to share), this creates a "hole" in the lattice structure, which can accept electrons.

4. **Identifying the Right Impurity**:
- The question provides several options: Phosphorus, Boron, Antimony, and Arsenic.
- Phosphorus and Antimony are pentavalent (having five valence electrons), and therefore, they do not create holes but instead donate extra electrons, making them n-type impurities.
- Boron, on the other hand, is trivalent (having three valence electrons) and is the correct impurity to create holes in the semiconductor.

5. **Conclusion**:
- The impurity atom needed to make a p-type semiconductor is Boron.

### Final Answer:
The impurity atoms needed to make a p-type semiconductor are **Boron**.