Question

What does an impurity amount of one part per million (ppm) mean?

Options

• One host atom per one million impurity atoms

• One impurity atom per one million atoms of the host

• One impurity atom per one million free electrons

• One hole per one million donor atoms

Answer 1

The amount of impurities can be expressed as parts per million (ppm). One ppm means one impurity atom per one million atoms of the host.