Diffusion of phosphorous and arsenic in germanium under in situ proton irradiation was performed and analyzed with secondary ion mass spectrometry. Dopant profiles corresponding to proton-exposed regions exhibit a higher penetration depth and more pronounced box shape than profiles of unexposed regions. Continuum theoretical simulations revealed that diffusion under irradiation was much less affected by inactive donor-vacancy clusters than diffusion under annealing only. The suppression of donor-vacancy clusters was caused by interstitials in supersaturation and vacancy concentrations close to thermal equilibrium. Concurrent annealing and irradiation had the potential to attain high active doping levels in Ge.

Suppression of Donor-Vacancy Clusters in Germanium by Concurrent Annealing and Irradiation. S.Schneider, H.Bracht: Applied Physics Letters, 2011, 98[1], 014101