THE EFFECT OF SAMPLE PREPARATION ON SPREADING RESISTANCE MEASUREMENTSOF DOPED SEMICONDUCTORS

The spreading resistance profiling (SRP) technique was used to investi gate the carrier concentration and segregation behavior of doped semic onductors. This technique is dependent on many parameters, in particul ar the surface finish of the wafers. The free-carrier concentration of the gallium (Ga)-doped germanium (Ge) [111] Czochralski grown crystal wafers were first measured using Hall effect measurements. The wafers were then prepared for SRP measurement with four different surface pr eparation procedures. These procedures were differentiated by the fina l polishing step used, namely; 0.1 mu m diamond polished-surface, 1 mu m alumina-polished surface, mechanochemical-polished surface using co lloidal silica, and a mechanochemical-polished surface which was then etched using a (1:1:1) HF:H2O2:CH3COOH etch, The measured SRP data for each surface were related to the Hall effect measurements by a probe calibration factor (PCF). A model was developed which related the tota l damage layer in each sample to the PCF. The total damage layer consi sts of the surface damaged region and the subsurface damaged region. U sing estimates from the literature, a linear relationship between the total damaged layer and the PCF was found.