The effect of sample preparation on spreading resistance measurements of doped semiconductors

• Published in: Journal of crystal growth 1997-04, Vol.174 (1), p.202-207
• Main Authors: Trujillo, A.H., Matthiesen, D.H.
• Format: Article
• Language: English
• Subjects: Characterization; Germanium; Segregation; Semiconductors; Spreading resistance
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/S0022-0248(96)01105-0

The spreading resistance profiling (SRP) technique was used to investigate the carrier concentration and segregation behavior of doped semiconductors. This technique is dependent on many parameters, in particular 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 preparation procedures. These procedures were differentiated by the final polishing step used, namely; 0.1 μm diamond polished-surface, 1 μm alumina-polished surface, mechanochemical-polished surface using colloidal silica, and a mechanochemical-polished surface which was then etched using a (1 : 1 : 1) HF : H 2O 2 : CH 3COOH 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 total damage layer in each sample to the PCF. The total damage layer consists of the surface damaged region and the subsurface damaged region. Using estimates from the literature, a linear relationship between the total damaged layer and the PCF was found.