A study was made of the electrical activity of defects which were created by high-dose MeV heavy-ion implantation of n-type material. Heavy damage, caused by Ar+ and Au+ ions, was present in the depletion layers of Schottky diodes. The defects were characterized by using capacitance-voltage, current-voltage, deep-level transient spectroscopy and time-analyzed transient spectroscopy techniques. Large concentrations of defects in the depletion layers of as-implanted devices led to unusual features in the capacitance-voltage and current-voltage characteristics. The damaged layer was found to extend, by several microns, beyond the ion ranges and damage profiles which were predicted by Monte Carlo simulations. The predominance of a single trap in the damaged region was established. Upon annealing (400-600C), the observed changes in the defect profile indicated that the effective electrical interface between damaged and undamaged layer moved progressively towards the surface. Transient spectroscopic analysis indicated that the major defect was a mid-gap trap whose energy was sensitive to the degree of disorder in the damaged layer. The experimental features were simulated by using model charge profiles. The simulations suggested the presence of a compensated region and of a sharp negatively-charged defect profile at a distance which was much greater than that expected on the basis of the ion range. These experimental results were in qualitative agreement with the predicted migration and clustering of interstitial-related defects, even at room temperature, in the case of high-dose irradiation.

Electrical characterization of MeV heavy-ion induced damage in silicon P.K.Giri, Y.N.Mohapatra: Journal of Applied Physics, 1998, 84[4], 1901-12