A solution to boron contamination at the substrate/epilayer interface of silicon grown by molecular beam epitaxy

The presence of a localized p⁺ spike at the substrate/epilayer interface of Si grown by molecular beam epitaxy (MBE) has been routinely found in material originating in various laboratories. The p‐type contaminant has been identified as boron with typical areal densities of ∼10¹² cm⁻², only part of which are electrically active after growth. The contamination arises from the use of borosilicate glassware in the MBE system (e.g., viewports), and the problem can be eliminated by replacing such components by quartz counterparts.