Molecular Beam Mass Spectrometry Studies of Chemical Vapor Deposition of Diamond

We have developed a novel molecular beam mass spectrometry technique that can quantitatively analyze the gas-phase composition in a chemical vapor deposition (CVD) reactor. The technique simultaneously monitors a wide variety of radical and stable species, and their concentrations can be determined with sensitivities approaching 1 ppm. Measurements performed in a diamond deposition system have provided keen insights into the important phenomena that affect the growth environment. In this paper we first discuss the primary gas sampling design issues. In the second part, details of the experimental results and their implications are described.