Mechanism of boron diffusion in amorphous silicon.
We have elucidated the mechanism for B migration in the amorphous (a-) Si network. B diffusivity in a-Si is much higher than in crystalline Si; it is transient and increases with B concentration up to 2 x 10(20) B/cm(3). At higher density, B atoms in a-Si quickly precipitate. B diffusion is indirect, mediated by dangling bonds (DB) present in a-Si. The density of DB is enhanced by B accommodation in the a-Si network and decreases because of a-Si relaxation. Accurate data simulations allow one to extract the DB diffusivity, whose activation energy is 2.6 eV. Implications of these results are discussed.
MATIS INFM-CNR and Dipartimento di Fisica e Astronomia, Università di Catania, via S. Sofia 64, Catania, Italy.
Salvatore
S
Mirabella
Davide
D
De Salvador
Elena
E
Bruno
Enrico
E
Napolitani
Emanuele F
EF
Pecora
Simona
S
Boninelli
Francesco
F
Priolo