Published online by Cambridge University Press: 10 February 2011
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 (wf) topography with high resolution (<0.1 meV), Surface Photovoltage (SPV) measurement and the acquisition of SPV transients with time constants down to I ts. This permits quasi-simultaneous determination of surface charge, surface barrier height and bulk minority carrier lifetime. Monitoring variations of these parameters after chemical treatments give an accurate indication of the location and amount of contamination.
The SKP system is introduced and the SPV and SPV transient measurement modes are discussed. Measurements on Fe-contaminated and Au-implanted Si wafers demonstrate the feasibility of the system for defect and impurity characterisation in semiconductors. The system is both non-contact and non-destructive, requires no wafer preparation and can be applied in both ambient and vacuum environments.