Determination of the chemical composition of electron cyclotron resonance microwave plasmas suitable for diamond deposition

Supersonic pulse, plasma sampling mass spectrometry is a new technique capable of providing a snapshot of the chemical composition of low-pressure plasmas or other difficult to probe environments. This technique has been demonstrated to be capable of addressing a wide range of chemical issues in materials processing with plasmas. Among the accomplishments of this technique have been the identification of a pseudoequilibrium or a fast interconversion of species (C₂H to C₂H₅) in various hydrocarbon/hydrogen electron cyclotron resonance microwave plasmas suitable for diamond deposition and the identification of SiCl as the major etch product in ECR-microwave plasma etching of silicon with chlorine. This work can be divided into two distinct research areas. The first and major portion of this research has been focused on probing the plasma environment to elucidate a possible reaction pathway for the deposition of diamond thin films. The second component has concentrated on possible pathways of thermal decomposition of hydrogen azide during nitridation processes.; In the primary study, four hydrocarbon sources were used (ethane, ethylene, acetylene, and methane) in conjunction with hydrogen and deuterium to generate a plasma suitable for diamond deposition. Each was investigated individually. The hydrocarbons which consisted of at least two carbons present in the parent molecule showed that the heavily hydrogenated species converted to lesser hydrogenated species, resulting in the plasma consisting of acetylenes. The methane was slowly coupled to the C₂ region of the manifold, however, did follow the same interconversion pattern once present in that region of the overall reaction scheme.