In semiconductor physics, the process of deliberately adding small amounts of suitable impurity atoms to a pure (intrinsic) semiconductor crystal in order to modify its electrical conductivity is called what?

Introduction / Context:

Semiconductors such as silicon and germanium are the foundation of modern electronics. Their electrical properties can be precisely controlled by introducing very small amounts of impurity atoms. This process allows the creation of p type and n type materials used in diodes, transistors and integrated circuits. The question asks for the technical term used to describe this intentional addition of impurities to a pure semiconductor.

Given Data / Assumptions:

• We start with a pure or intrinsic semiconductor crystal.
• Small quantities of impurity atoms (donors or acceptors) are introduced.
• The goal is to change carrier concentration and hence conductivity.
• The process is controlled and deliberate, not accidental contamination.

Concept / Approach:

The intentional addition of impurity atoms to a semiconductor is called doping. Donor impurities (such as phosphorus in silicon) create extra free electrons, producing n type material, while acceptor impurities (such as boron in silicon) create additional holes, producing p type material. Doping levels can range from very light to very heavy, allowing fine tuning of device characteristics. The other words in the options, like mixing, forming or diluting, are generic and do not capture the specific semiconductor engineering meaning.

Step-by-Step Solution:

Verification / Alternative check:

Electronics textbooks consistently describe n type and p type semiconductors as doped semiconductors. Processes such as diffusion doping and ion implantation are standard in semiconductor fabrication. None of these processes are referred to as simply mixing or diluting, which further confirms that doping is the accepted term.

Why Other Options Are Wrong:

Option B: Mixing is a very general word and does not convey the precise meaning of controlled impurity addition in crystal lattices.

Option C: Forming may refer to shaping or manufacturing devices but is not the specific term for adding impurity atoms.

Option D: Diluting would suggest reducing concentration by adding more of a solvent or host, which is the opposite of what is done in doping, where small quantities of impurities are added to increase carrier concentration.

Common Pitfalls:

Some learners confuse doping in semiconductor context with everyday use of the term in sports. In electronics, doping is a neutral technical term with no negative connotation. Another point of confusion is to think any contamination is doping, but in device fabrication, doping is carefully controlled in type and concentration, unlike accidental contamination which is undesirable.

Final Answer:

The process is called Doping.