CONFOCAL IMAGING OF POROUS SILICON WITH A SCANNING LASER MACROSCOPE MICROSCOPE

High resolution, large area photoluminescence mapping with scanning st age microscopes has proven to be a useful, but slow, quality control t echnique for compound semiconductor wafers. This paper describes a con focal scanning beam MACROscope-Microscope which can image specimens up to 7.5 x 7.5 cm in size, in less than 10s, using reflected light, pho toluminescence, and optical beam induced current. MACROscope mode prov ides 5 mu m lateral resolution and 300 mu m axial resolution. Microsco pe mode provides 0.25 mu m lateral and 0.5 mu m axial resolution, with a minimum field of view of 25 x 25 mu m. This instrument can be used to evaluate preparation parameters involved in the manufacture of poro us silicon as well as to provide quality control at a macroscopic and microscopic level for the fabrication of porous silicon specimens, waf ers, detectors, and similar devices. A brief introduction to confocal microscopy and porous silicon is given. Several confocal and non-confo cal photoluminescence and reflected-light images of a porous silicon w afer are shown at macroscopic and microscopic levels. A 3D profile of porous silicon structures reconstructed from confocal slices is also s hown.