Micro- to Nano-Characterization of Semiconductor Grain Boundaries

This paper examines the use of surface-analysis methods in the characterization of grain boundaries in semiconductors. The purpose is to demonstrate the utility of increasing spatial resolution in the evaluation of defects. Three distinct mechanisms for adjusting the electronic properties of defect regions of semiconductors are presented. These include the passivation of grain boundaries by chemical methods; the electrical neutralization of shallow acceptor impurities; and, the doping of the defect regions. Secondary ion mass spectrometry, Auger electron spectroscopy and specialized scanning tunneling microscopy are used to evaluate the grain-boundary structure, composition and chemistry. Complementary macro- and nano-electro-optical characterization techniques based on electron-beam-induced current and photoluminescence provide correlated information on the effects of the chemical-treatment methods.