A novel detection system for defects and chemical contamination in semiconductors based upon the Scanning Kelvin Probe

A novel wafer scale detection system for defects and chemical contamination in semiconductors based upon the Scanning Kelvin Probe (SKP) is presented. It incorporates traditional work function (phi) topography with high resolution (<0.1 meV). surface photovoltage (SPV) measurement and surface photovoltage-deep level transient spectroscopy (SPV-DLTS). This permits quasi-simultaneous determination of surface charge, surface potential and carrier lifetime, as well as the characterisation of deep level defects. The SKP system is introduced and the SPV and SPV-DLTS measurement modes are discussed. Surface charge measurements on clean and Fe-contaminated p-type Si(100) wafers show that iron induces negative charge in both native and thermally grown oxide layers. SPV-DLTS is demonstrated on defects in thermally oxidised Si. The system is both non-contact and non-destructive. requires no wafer preparation, and can be applied in both ambient and vacuum environments. (C) 1999 Published by Elsevier Science B.V. All rights reserved.