Krypton is a colorless, odorless, tasteless inert gas that is about twice as heavy as air. It is not active and does not burn or help to burn. The amount of krypton gas in the air is very small, only 1.14ml per 1m3 of air.

Etching is the process of using chemical and physical methods to selectively remove unwanted materials from the surface of a silicon wafer.

Boron trifluoride is an important catalyst widely used in organic synthesis and petrochemical industry. It is used in many organic chemical reactions such as alkylation, polymerization, isomerization, addition, synthesis and decomposition.

standard gas is a mixture of gases with an accurate known concentration