Luminescence from erbium implanted silicon-germanium quantum wells

We have investigated the luminescence emitted at 1.54 mu m from erbium-impl anted strained ultrahigh vacuum chemical vapor deposition-grown (UHVCVD-gro wn) Si1-xGex quantum wells. Germanium fractions of up to 13% were used, and all well widths were below the critical thickness for pseudomorphic growth . A preliminary study was carried out on Si1-xGex quantum wells implanted w ith amorphizing doses of silicon at 77 K in order to study the regrowth acr oss the interfaces, and subsequent structural and optical recovery. After a morphization and regrowth by a two stage anneal process, transmission elect ron microscopy (TEM) clearly showed the presence of the quantum wells, with sharp contrast. X-ray diffraction (XRD) studies showed that good regrowth has been achieved, with Line widths very similar to the original material. However, the photoluminescence (PL) was found to be dependent upon the dura tion of the first anneal. Increasing the anneal time resulted in PL spectra being dominated by broad signals between 0.9 and 0.97 eV associated with s tructural defects. High concentrations of erbium were incorporated into the strained Si1-xGex quantum wells by implantation and solid phase epitaxial regrowth. TEM and XRD studies showed that the quantum wells retained their structure, with negligible segregation or diffusion of the germanium during the recrystallization. Erbium-related emission centered at 1.54 mu m was o bserved in the implanted Si1-xGex layers after regrowth, and generally foun d to be of similar intensity as that in bulk silicon implanted with more th an an order of magnitude higher dose of erbium. (C) 1998 American Vacuum So ciety. [S0734-211X(98)01206-2].