Background and Objectives: The laws governing the modification of the current-voltage characteristics of the metal-insulatorsemiconductor structures due to the formation of embedded surface potentials are investigated. Surface potentials are formed when an atomically clean surface of silicon crystals is produced using microwave plasma micromachining. The aim of the work is to study the effect of plasma micromachining in various chemically active gaseous media on the properties of silicon MIS structures.