Characteristics of fast ions from laser-induced plasma and their applicability to shallow junction doping

The characteristics of fast ions generated from laser-induced plasma on a boron solid target have been studied for an application to shallow junction doping. The peak position in the produced B ion energy spectra can be controlled in a 150–550 eV range by changing the laser intensity. From the measurement of B ion energy spectrum which was resolved into charge states at several laser intensities, most part of the energy spectra around the peak position was found to be composed of B+ ions at the laser intensity less than 3.0 × 1010 W/cm2. The number of produced ions around the peak of the energy spectrum was about 2 × 1012 ions/(eV·Sr) or higher within the emission angle smaller than 45°. These results indicate that the produced B+ ions are applicable to shallow doping in a sub-10 nm range.