Lattice location and stability of implanted Cu in Ge

✍ Scribed by U. Wahl; J.G. Correia; J.C. Soares

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 325 KB
• Volume: 340-342
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2003.09.216

✦ Synopsis

We report on emission channeling experiments using the radioactive isotope 67 Cu implanted into single crystalline i-Ge at a fluence of 2.4 Â 10 12 cm À2 . The lattice location of 67 Cu was determined from the angular-dependent b À emission yield, which was measured by means of a position-sensitive detector around the /1 1 1S, /1 0 0S and /1 1 0S directions. We find that already in the as-implanted state a considerable fraction of Cu (20-25%) occupies ideal substitutional lattice positions, a similar fraction is located on positions that are displaced around 0.5-0.6 ( A from substitutional sites. Following annealing at 300 C for 10 min, the substitutional fraction of implanted Cu increased to 45% while the fraction of displaced Cu decreased to 23%. Upon further annealing at 400 C, channeling effects disappeared completely and around 10% of 67 Cu diffused out of the Ge sample. From this we can estimate the activation energy for dissociation of substitutional Cu to be around 1.6-1.9 eV.