Simplified Method of Determining the Occurrence of Dopant Redistribution During the Thermal Oxidation of Silicon
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02
The described method permits determining the occurrence of dopant redistribution during the thermal oxidation of silicon, without measuring the sputter rate. SIMS (secondary ion mass spectrometry) is generally used to determine doping profiles in silicon at high doping levels. This method necessitates an in-situ measurement of the sputter rate which is not constant but depends on the respective doping level. SIMS measurements have shown that equal quantities of silicon are removed in a given time by sputtering with O+ (at 12 keV), irrespective of whether the silicon was previously oxidized or not. This indicates that the removal mechanism is the same in either case, i.e., that all the silicon in a thin surface layer is initially converted into SiO2 by O+ bombardment and simultaneously removed.