Annealing studies of cluster defects in ion-implanted silicon using high resolution DLTS

✍ Scribed by M.A. Gad; J.H. Evans-Freeman

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 166 KB
• Volume: 253
• Category: Article
• ISSN: 0168-583X
• DOI: 10.1016/j.nimb.2006.10.020

✦ Synopsis

High resolution Laplace deep level transient spectroscopy (LDLTS) has been applied to investigate the annealing behaviour of small cluster defects in n-type Si. The Si was implanted with either Ge or Si, with energies 1500 keV and 850 keV respectively, and doses of 1 • 10 10 cm À2 . The low dose ensured that there was a minimum of carrier removal due to deep defect states after implantation. Defect states in the as-implanted samples were attributed to VO pairs, divacancies and very small interstitial cluster defects, after detailed depth profiling. LDLTS of Ge + and Si + implanted silicon shows that there are three closely spaced deep levels associated with these clusters, with energies in the region of E c -400 meV. Samples were then isochronally annealed in very small temperature intervals up to 560 K, in situ in our high temperature measurement cryostat, and the LDLTS re-examined as a function of annealing temperature. A new deeper energy level emerges as the cluster-related signal reduces, and it is suggested that this new trap is a major recombination centre, by comparison with current-voltage data.