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 1.0x10(13) to 1.0x10(15) cm(-2) and can be removed by rapid thermal annealing for 30 s at 600-800 degrees C, as evidenced by the variation of the full width at half-maximum of the A(1)-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 degrees C after P implantation of 1.0x10(15) cm(-2). Furthermore, by annealing at 600 and 700 degrees C, P atoms have been revealed to segregate into the surface and BaSi2/Si interface while the P segregation is suppressed at 800 degrees 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. (C) 2013 Elsevier B.V. All rights reserved.