Secondary-Ion-Mass-Spectrometry Depth Profiling of Ultra-shallow Boron Delta Layers in Silicon with Massive Molecular Ion Beam of Ir4(CO)7+

Tetrairidium dodecacarbonyl, Ir4(CO)12, is a massive compound called metal cluster complex, which has a molecular weight of 1104.9. Using an Ir4(CO)7+ primary ion beam, secondary ion mass spectrometry (SIMS) of boron-delta-doped silicon samples was performed. Depth resolution, defined by 1/e decay length for the trailing edge of the boron delta layer, was investigated in the beam energy ranging from 2.5 to 10 keV at an incident angle of 45°. Experimental results showed that the depth resolution improved with oxygen partial pressure at a beam energy of 5 keV. It was confirmed that the depth resolution without oxygen flooding monotonically improved as beam energy decreased. Furthermore, it was found that the favorable effect of oxygen flooding on depth resolution weakened as beam energy was reduced.