Suppression of interfacial boron accumulation and defect density in molecular beam epitaxial silicon

A low temperature substrate surface cleaning procedure for silicon MBE has been studied. By using HF dipping followed by a two-step annealing, we achieved great suppression of the interfacial boron spike down to the concentration below 1015 cm-3 and reduction of the density of deep level defects down to below 1012 cm-3. The preheating temperature to obtain a clear (2 × 1) RHEED pattern can also be lowered to 300–400°C.