Application of Positron Annihilation in the Si Integrated Circuit (IC) Industry

Currently the trend in the Si IC industry is to produce epitaxial material layers by advanced growth and deposition techniques. Examples of these are Si and SiGe low temperature epitaxy, Si selective epitaxy and metallic silicide epitaxy. In order to obtain good electrical properties it is important that the epitaxial material shows no extended lattice defects and has a minimal concentration of lattice point defects. Given the concentrations of these phenomena a sensitive experimental technique is required to characterise the materials. The application of the positron annihilation technique in this IC research area is demonstrated by two examples, namely, characterization of Si Molecular Beam Epitaxy (MBE) and Atmospheric Pressure Chemical Vapour Deposition (APCVD) epi-layers and the assessment of the quality of CoSi, epi-layers produced by the solid-state reaction with the Si substrate and an amorphous Co7,W,, sputtered layer. Results will be presented in terms of defect concentrations derived from positron diffusion lengths.