Hydrogen in Si: Diffusion and shallow impurity deactivation

✍ Scribed by M. Capizzi; A. Mittiga

• Publisher: Elsevier Science
• Year: 1987
• Weight: 992 KB
• Volume: 146
• Category: Article
• ISSN: 0378-4363
• DOI: 10.1016/0378-4363(87)90048-9

✦ Synopsis

A review of theoretical and experimental aspects of hydrogen diffusion and shallow impurity passivation in semiconductors is presented.

Fitting of hydrogen concentration profiles in p-type hydrogenated silicon is for the first time attempted for atomic hydrogen diffusion with trapping-detrapping near the boron impurities, allowing also for molecule formation. Failure to account for the experimental behavior is apparent.

Fittings of the same experimental data are successfully achieved in terms of a new model which postulates a H-donor state within the band gap and results in neutral hydrogen diffusion plus electric field drift. The thermal activation energies for the diffusion of neutral and ionized hydrogen, 1.22 eV and 0.8 eV, differ by as much as the hydrogen donor binding energy, 0.45 eV. The diffusivity of neutral hydrogen follows an exponential behavior over twelve decades between room temperature and 1200°C. The dependence on impurity type of the hydrogen penetration depth is also accounted for.