Epitaxial growth of pure 28Si thin films using isotopically purified ion beams

Isotopically purified Si-28 homoepitaxial films were grown by means of an ion-beam deposition (IBD) method with isotopically mass-selected negative Si-28(-) ion beams. The surface structural evolution during the film growth and the film structure after the growth were investigated using reflection high-energy electron diffraction (RHEED), cross-sectional transmission electron microscopy (TEM) and transmission electron diffraction (TED). The Si isotopic composition (Si-28 : Si-29 : Si-30 = 99.9982 : 0.0016 : 0.0002 at.%) of the resulting Si epitaxial film was determined by secondary-ion-mass spectrometry (SEAS).