Scanning near-field optical microscopy in semiconductor research

Exploration of optical properties of materials and optical characterization of structure defects at the nanometer scale was impossible until recently due to the diffraction limit of light. With the invention of scanning near-field optical microscopy (SNOM), resolution at the 50-100 nm level using visible or near infrared light is now possible. This review focuses on some applications of SNOM to the characterization of semiconductor devices, with an emphasis on defects. The unique capability of SNOM to simultaneously measure! surface topography and local optoelectronic properties, thereby eliminating the need to perform cross correlation analysis on results obtained using different techniques, is particularly useful in this area. Several examples are discussed.