Photothermoacoustic and photoelectric microscopy of silicon

Combined photothermoacoustic and photoelectric microscopy is used to invest igate silicon-based structures: an epitaxially grown n-type region in a p-t ype substrate, a p-p(+) interface obtained by implanting boron ions, and a region near a crack tip. It is concluded that the visualization of epitaxia l regions by thermal waves most probably stems from the elastic stresses ap pearing during fabrication of the structures. It is shown that the spatial distribution of the elastic stresses appearing upon ion implantation is vis ualized by thermal waves. In the region near the crack tip inhomogeneities in the thermoelastic and energy properties extending over hundreds of micro ns can be diagnosed by thermal waves and electron-hole plasma waves. Spatia l periodicity with a period similar to 85 mu m is discovered in the variati on of the thermoelastic properties near the crack tip. (C) 1999 American In stitute of Physics. [S1063-7826(99)01206-5].