Binding of copper and nickel to cavities in silicon formed by helium ion implantation
Cavities formed in Si by He ion implantation and annealing are shown to be strong traps for Cu and Ni impurities. Experiments utilizing ion-beam analysis and transmission electron microscopy indicate that Cu is trapped at the internal surfaces of cavities up to {approximately}1 monolayer coverage with a binding energy of 2.2{plus_minus}0.2 eV relative to solution. This is greater than the heat of solution from the precipitated Cu{sub 3}Si phase, determined to be 1.7 eV in agreement with earlier work. Copper at cavity-wall sites is reversibly replaced by H during heating in H{sub 2} gas, indicating the relative stability of the two surface terminations. Initial results for Ni impurities indicate that trapping at cavities is again energetically preferred to silicide formation. The saturation coverage of Ni on the internal surfaces, however, is an order of magnitude smaller for Ni than Cu, consistent with published studies of external-surface adsorption. These results suggest that cavity trapping may getter metallic impurities in Si more effectively than methods based on silicide precipitation.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 10106684
- Report Number(s):
- SAND-93-1453C; CONF-931108-7; ON: DE94003769; BR: GB0103012; TRN: 94:000873
- Resource Relation:
- Conference: Fall meeting of the Materials Research Society (MRS),Boston, MA (United States),29 Nov - 3 Dec 1993; Other Information: PBD: [1993]
- Country of Publication:
- United States
- Language:
- English
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