Secondary Ion Mass Spectroscopy

Secondary ion mass spectroscopy uses a high energy ion beam to sputter solid samples.  The mass spectrometer then separates and counts the ions that are expelled from the sample.  The result is an analysis of the elemental concentration in depth from the surface into the bulk.  The magnetic sector SIMS instrument uses high energy beams (1 keV to 15 keV) with a high extraction field to provide fast sputter rate – high sensitivity depth profiling.  Major applications are trace element contamination  for many  Si and III-V based semiconductors.  For example  trace contamination in bulk films and materials, implant characterization, thin film composition and device dopant analysis.  Using NIST traceable standards the results can be quantified.  For secondary ion mass spectroscopy analysis the minimum sputter area is 100 X 100 microns so generally there needs to be a specific test structure on patterned wafers or a blanket wafer is necessary.

Quadrupole SIMS instruments use low extraction fields to extract secondary ions from the sample.  Low energy ion bombardment, gives higher depth resolution and allows for analysis of ultra-shallow implants and very thin films. Because of the low extraction fields of the Quad-SIMS instrument, it is easier to do charge compensation for the analysis of insulating material like SiO2 and Si3N4. We have developed protocols for H analysis in Si- rich nitrides, B and P concentrations in BPTEOS, N concentration in thin oxynitride films, and Ge concentration in SiGe samples with OCE (Optical Conductivity Enhancement).

Instruments: