Mass-spectrometer-controlled fabrication of Si/Ge superlattices

Abstract

We have used a quadrupole mass spectrometer to control deposition rates during fabrication of compositionally modulated Si/Ge superlattices. Its performance has been evaluated by an x-ray diffraction study of a superlattice. The variation of the Si deposition rate was less than 3% during the whole deposition time of 30 min. This proves that a mass spectrometer can be successfully employed as rate monitor in Si molecular beam epitaxy systems.