Boron incorporation with and without atomic hydrogen during the growth of doped layers on Si(100)

Abstract

Solid source molecular beam epitaxy Si growths were done with and without atomic hydrogen (AH) to investigate the impact of AH on B segregation and activation. A series of 3 or 50 nm thick B-doped Si layers separated by 200 nm of undoped Si were grown at 0.1 nm/s on Si(100) substrates. In separate experiments, 10−4 Pa of AH was applied after (at 500, 600, and 710 °C) or during (at 710 °C) the 3 nm B-doped layer to determine if AH affected segregation. AH was applied before the 50 nm B-doped layer to observe if AH increased B activation between 600 and 800 °C. It was found that application of AH after the growth of the 3 nm B-doped layer had no effect on B segregation through 600 °C and increased B segregation at 710 °C, as measured by secondary ion mass spectrometry (SIMS). Application of AH during B-doped Si layer growth had no effect on B segregation. Application of 10−3 Pa of AH for 100 s prior to growth of the 50 nm B-doped layer improved surface order, as measured by low energy electron diffraction, and, at T⩾700 °C, increased B activation, as measured by spreading resistance profilometry (SRP). The differences between the SIMS and SRP data are postulated to be due to two forms of B: one electrically active and the other electrically inactive. The electrically inactive form is modeled by two paired B atoms on adjacent substitutional sites.