The sensitivity of positron annihilation spectroscopy to process parameters associated with the formation of buried oxide layers in Si was investigated and evaluated. Ion beam current density, implantation temperature, and ion dose and energy were varied over ranges used in standard and low-dose SIMOX formation. Whereas the positron Doppler broadening parameter for as-implanted samples was found to have no measurable sensitivity to low-energy ion current density, the results suggested that there was a small dependence upon implantation temperature. More significantly, positron annihilation spectroscopy was highly sensitive to changes in dose of a few percent, and to ion energy. The results for as-implanted samples suggested that beam-based positron annihilation spectroscopy was an ideal method for improved dose control, particularly during the formation of low-dose SIMOX. Measurements on fully-formed SIMOX samples were also rich in information related to the structure of the samples.

Positron Annihilation Spectroscopy as a Diagnostic Tool for Process Monitoring of Buried Oxide Layer Formation in Si. P.G.Coleman, A.P.Knights, M.J.Anc: Journal of Applied Physics, 2003, 93[1], 698-701