Published online by Cambridge University Press: 26 February 2011
The dislocation density in undoped Si-MBE layers grown on wafers without any chemical pre-cleaning has been studied. The oxide layer was removed using a low silicon flux. Factors influencing the dislocation density have been studied, including substrate type, growth temperature and the temperature at which oxide is removed. Dislocation densities below 10-3 cm-2 have been obtained. The defect density in p-type silicon doped with boron oxide has also been studied. The influence of boron oxide on dislocation density has been found to be negligible, even though incorporation of oxygen is large at growth temperatures ≤650°C. Boron oxide doped Si.88Ge.12 layers have also been grown and a similar level of dislocations has been found.