We report on Au-diffusion experiments performed between 850°C and 1100°C into plastically deformed Si monocyrstals, undoped and uniformly doped with a B concentration of 3×1019 cm-3. After indiffusion, Au profiles were monitored with neutron activation analysis (NAA) in conjunction with mechanical sectioning. The profiles show Au-diffusion to be faster in heavily B-doped Si than in undoped samples. Fitting of the experimental profiles which are accurately described with complementary error functions yields an effective diffusion coefficient DAueff and a boundary concentration CAu(x=0). Data for DAueff and CAu(x=0) obtained for diffusion temperatures lower than 1000°C are considerably lower and higher, respectively, than expected from the extrapolation based on the high-temperature results. The unusual temperature dependence of DAueff and CAu(x=0) is explained taking into account segregation of Au at dislocations in addition to the kick-out diffusion mechanism which is the generally accepted process for Au diffusion in dislocation-free Si. The segregation of Au at dislocations is found to increase with decreasing temperature with an activation enthalpy of about -1.9 eV. From the influence of doping observed on Au diffusion into dislocated Si, we deduce that interstitial Au is positively charged in p-type Si and introduces a donor level at about 0.47 eV above the valence-band edge.
|ジャーナル||Materials Science Forum|
|出版物ステータス||Published - 1997 1 1|
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering