Structural study on phosphorus doping of BaSi2 epitaxial films by ion implantation

Phosphorus doping of BaSi2 epitaxial films by means of P implantation and rapid thermal annealing has been investigated from a structural viewpoint. Raman spectroscopy and X-ray diffraction show that the crystal structure of BaSi2 is destroyed, at least partially, by P implantation. This irradiation damage increases with increasing the P dose from 1.0 × 1013 to 1.0 × 1015 cm− 2 and can be removed by rapid thermal annealing for 30 s at 600–800 °C, as evidenced by the variation of the full width at half-maximum of the A1-mode Raman peak. In addition to the recovery of the irradiation damage, the metastable trigonal phase of BaSi2, which is metallic and undesirable to exist in the semiconductor film, is found to form by annealing at 800 °C after P implantation of 1.0 × 1015 cm− 2. Furthermore, by annealing at 600 and 700 °C, P atoms have been revealed to segregate into the surface and BaSi2/Si interface while the P segregation is suppressed at 800 °C, according to the depth profile of P determined by secondary ion mass spectroscopy. Thus, we have obtained a useful guide of the P implantation dose and annealing temperature to effectively dope P atoms into the semiconducting BaSi2 film.

► P doping of BaSi2 by ion implantation and rapid thermal annealing is studied.
► The crystal structure of BaSi2 is destroyed, at least partially, by P implantation.
► The annealing condition to remove the irradiation damage is revealed.
► The trigonal BaSi2 phase forms from the highly damaged film by annealing.
► P atoms segregate at 600–800 °C.