Determination of Amorphous Layer Thickness in Ion Implanted Silicon Using Secondary Ion Mass Spectrometry

摘要

Secondary ion mass spectrometry has been used to study boron-doped Si (100) that was rendered amorphous by the implantation of (75)As. Using oxygen bombardment and negative secondary ion detection, all secondary ion species show a shift in ion energy of greater than 2eV upon sputtering through the amorphous layer and into the underlying crystalline silicon. After regrowth of the same specimens by rapid thermal annealing, the secondary ion energy shift occurs significantly deeper, at approximately the p-n junction. In both specimens, the energy shift was shown to be due to bombardment-induced specimen charging. Thus, the thickness of the amorphous layer in the As-implanted specimen can be determined by profiling with a narrow secondary ion energy window. Mechanisms for this effect are discussed. Keywords: Secondary ion mass spectrometry, depth profiling, ion implantation, amorphous silicon.