Boron Detection Technique in Silicon Thin Film Using Dynamic Time of Flight Secondary Ion Mass Spectrometry

The impurity concentration is a crucial parameter for semiconductor thin films. Evaluating the impurity distribution in silicon thin film is another challenge. In this study, we have investigated the doping concentration of boron in silicon thin film using time of flight secondary ion mass spectrometry in dynamic mode of operation. Boron doped silicon film was grown on i) p-type silicon wafer and ii) borosilicate glass using hot wire chemical vapor deposition technique for possible applications in optoelectronic devices. Using well-tuned SIMS measurement recipe, we have detected the boron counts 101~104 along with the silicon matrix element. The secondary ion beam sputtering area, sputtering duration and mass analyser analysing duration were used as key variables for the tuning of the recipe. The quantitative analysis of counts to concentration conversion was done following standard relative sensitivity factor. The concentration of boron in silicon was determined 1017~1021 atoms/cm3. The technique will be useful for evaluating distributions of various dopants (arsenic, phosphorous, bismuth etc.) in silicon thin film efficiently.