The Diffusion of Ion-Implanted Arsenic in Silicon

In order to characterize implanted-diffused As layers in Si and to develop general processing information, impurity profiles were determined by secondary ion mass spectrometry (SIMS) and differential conductivity measurements. An analysis of these profiles is given which has yielded information regarding the diffusion of As and the electrical quality of these implanted-diffused layers. It is shown that implanted-diffused As profiles with CTO ≥ 1 × 1020 cm-3 can be described by a Chebyshev polynomial approximation to the diffusion equation with concentration-dependent diffusivity. The diffusion of As is not dependent upon the furnace ambient, but As pile-up within 200-400A of the Si surface does occur during diffusion in an oxidizing atmosphere. It is also shown that implanted-diffused As layers show higher electrical activity for diffusion temperatures below 1100°C than layers diffused from chemical sources. For implanted As layers in which the peak concentration is greater than the solubility limit, the fraction of electrically active As increases at a rate proportional to t1/3. © 1975, The Electrochemical Society, Inc. All rights reserved.

Duke Scholars

Author Richard B. Fair Electrical and Computer Engineering