Scanning Acoustic Microscopy and SIMS investigation of CdTe detectors

The performance of both CdTe and CZT detectors depend largely on the qualit y of the contacts as well as on the surface preparation procedures. In gene ral, electroless deposition contacts of either Au or Pt are used to prepare nearly ohmic contacts. These contacts are rather complicated in their stru cture and often failures or instabilities are observed. In this paper, we h ave investigated these surface areas by scanning acoustic microscopy. a met hod which is used for the first time to our knowledge to characterise these contact layers. By measuring the acoustic signal at various points of cont acted samples, information on the surface uniformity can be obtained. These measurements have been complemented by SIMS measurements, giving the chemi cal distribution in the near-surface region of the elements of interest. (C ) 2001 Elsevier Science B.V. All rights reserved.