レーザーSQUID顕微鏡による半導体検査

概要

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We developed a laser SQUID microscope that consists of a high-temperature superconducting SQUID magnetometer and lasers. By illuminating a laser beam onto a semiconductor, photo-currents are generated, and small magnetic fields are thereby induced. The SQUID detects photo-induced magnetic signals on semiconductors with amplitudes of several hundred femto-teslas. Micrometer-leve1 spatial resolution can be realized by using a focused laser, without reducing the SQUID's coil diameter, and thus high sensitivity can be maintained. We carried out visualizations of the photo-induced magnetic field distribution for silicon p-n junctions, multi-crystal grain boundaries and GaN blue light-emitting diodes, and performed quantitative measurement of the carrier diffusion length. The laser SQUID microscope has the potential to become a new tool for evaluation, because it offers nondestructive, non-contact, contamination-free, and non-pretreatment access to semiconductors.
社団法人日本磁気学会の論文
2005-01-01