The visualisation of so far not detectable defects in electronic grade Si was achieved by improving the sensitivity of a microwave detection system by several orders of magnitude. This approach to a new detection scheme opens possibilities for a variety of contact-less non-destructive electrical defect characterisation methods which could be applied to high-quality Si wafers and even to thin epitaxial layers. Electrical properties such as lifetime, mobility and diffusion length could be measured even at low injection levels with a spatial resolution only limited by the diffusion length of the charge carriers. The doping level of the material plays no major role. Due to the high sensitivity a microwave absorption signal caused by carrier emission from defects could be observed even in high-quality material at low injection levels. This allows for the first time the electrical investigation of the well-known thermal donor also in electronic grade p-doped silicon, which was not feasible with deep level transient spectroscopy. Temperature treatment of such samples allows new insight into the transformation of threading dislocations during annealing. Furthermore, the correlation with photoluminescence spectroscopy allows for an assignment of deep levels, which could be investigated by microwave-detected–photo-induced current transient spectroscopy (MD–PICTS).

Contactless Electrical Defect Characterisation of Silicon by MD-PICTS. K.Dornich, K.Niemietz, M.Wagner, J.R.Niklas: Materials Science in Semiconductor Processing, 2006, 9[1-3], 241-5