The diffusion and activation of n-type impurities (P and As) implanted into p-type Ge(100) substrates were examined under various dose and annealing conditions. The secondary ion mass spectrometry profiles of chemical concentrations indicated the existence of a sufficiently high number of impurities with increasing implanted doses. However, spreading resistance probe profiles of electrical concentrations exhibited electrical concentration saturation in spite of increasing doses and indicated poor activation of As relative to P in Ge. The relationships between the chemical and electrical concentrations of P in Ge and Si were calculated, taking account of the effect of incomplete ionization. The results indicated that the activation of P was almost the same in Ge and Si. The activation ratios obtained experimentally were similar to the calculated values; implying insufficient degeneration of Ge. The profiles of P in Ge substrates, with and without damage generated by Ge ion implantation, were compared and it was clarified that the damage that could compensate the activated n-type dopants bore no relationship to the activation of P in Ge

Diffusion and Activation of n-Type Dopants in Germanium. M.Koike, Y.Kamata, T.Ino, D.Hagishima, K.Tatsumura, M.Koyama, A.Nishiyama: Journal of Applied Physics, 2008, 104[2], 023523