Dopant-defect interactions in highly doped epitaxial Si:P thin films

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Clustering configurations and reactions within in-situ doped epitaixal Si:P films were investigated. In-situ highly doped epitaxial Si:P films (HDSiP) were grown by reduced-pressure chemical vapor deposition with phosphorus concentrations up to 4.4 × 1021 cm−3. Additional P activation in Si:P films into metastable states can be achieved by a 1200 °C millisecond laser anneal with negligible dopant diffusion. Dopant deactivation takes place readily during subsequent low temperature annealing for HDSiP despite negligible diffusion during the same time. Diffusion analysis of buried marker layers suggest a high concentration of interstitials being released from HDSiP and Si:P layers doped with sub 1 × 1021 cm−3 P concentrations. Upon thermal annealing. In addition, extrinsic dislocation loop formation was observed in sufficiently high P concentration HDSiP films. It is proposed that a high concentration of grown-in P-interstitial clusters exist concurrently with vacancy clusters theorized in HDSiP thin films.