Epitaxial growth rate measurements during molecular beam epitaxy

Apparent oscillations in surface temperature occur during the deposition of heteroepitaxial structures when measured using a narrow optical bandpass pyrometer. The oscillation period can be related to the growth rate of the material being deposited, and provides a convenient method for rapid in situ calibration. For Ga1−xAlxAs alloys the oscillation periods can be directly related to the alloy composition. The pyrometer optics can also be used in conjunction with external light sources so that simultaneous pyrometry and reflectrometry can be carried out at multiple wavelengths.