Behaviour of oxygen in CZ-silicon during 430–630°C heat

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Behaviour of oxygen in CZ-silicon during 430–630°C heat
treatment
Om Prakash, N.K Upreti
1
, Shyam Singh *
Department of Physics, G.B. Pant Uni6ersity of Ag. and Tech., Pantnagar 263 145, India
Received 23 July 1997; accepted 14 October 1997
Abstract
The generation of thermal donors (TDs) depends on initial oxygen concentration, annealing temperature and its duration. An
annealing process at 450°C for several hours generates upto :1016
cm3
TDs. We found that maximum concentration of TDs
formed at 480°C was :1.01015
cm3
which reduces to a minimum of :2.61014
cm3
at 510°C suggesting thereby that the
TDs got annihilated in this temperature range. The number of TDs now increases with a corresponding increase in annealing time
giving birth to new donors (NDs). Activation energy for oxygen diffusion was found to be 0.690.1 eV and of silicon self
interstitials :0.4 eV. Therefore, it is quite logical to conclude that oxygen diffusion at low temperatures depends on the transport
of the self interstitials which are chiefly due to the formation of molecule-like oxygen clusters. This confirms the formation and
diffusion of molecule-like oxygen clusters in silicon at low temperatures. © 1998 Elsevier Science S.A. All rights reserved.
Keywords: Thermal donors; New donors; Thermal acceptor; Kinetics; Dimers; Activation energy