Patent ID: 6075588
Filing Date: 2000-06-13
Classification: G01N

Abstract:
A method of monitoring atomic absorption of a plurality of atomic species during epitaxial growth on a substrate comprising the steps of:energizing at least two light sources so that light is emitted therefrom, each light source emitting a distinct wavelength corresponding to an atomic absorption transition for each corresponding atomic specie being monitored and modulated at a different modulation frequency;combining the light from the light sources;splitting the combined light into a reference arm and a signal arm;transmitting the light in the signal arm along an optical path through a flux of material being deposited on a substrate in a vacuum chamber; andcomparing each distinct wavelength emitted from each light source in the reference arm to the corresponding distinct wavelength corresponding to an atomic absorption transition for each corresponding atomic specie being monitored in the signal arm after the light in the signal arm has passed through the flux of material being deposited.