title: Fault localization and analysis in semiconductor devices with optical-feedback infrared confocal microscopy.
abstract: We report on a cost-effective optical setup for characterizing light-emitting semiconductor devices with optical-feedback confocal infrared microscopy and optical beam-induced resistance change. We utilize the focused beam from an infrared laser diode to induce local thermal resistance changes across the surface of a biased integrated circuit (IC) sample. Variations in the multiple current paths are mapped by scanning the IC across the focused beam. The high-contrast current maps allow accurate differentiation of the functional and defective sites, or the isolation of the surface-emitting p-i-n devices in the IC. Optical beam-induced current (OBIC) is not generated since the incident beam energy is lower than the bandgap energy of the p-i-n device. Inhomogeneous current distributions in the IC become apparent without the strong OBIC background. They are located at a diffraction-limited resolution by referencing the current maps against the confocal reflectance image that is simultaneously acquired via optical-feedback detection. Our technique permits the accurate identification of metal and semiconductor sites as well as the classification of different metallic structures according to thickness, composition, or spatial inhomogeneity.
authors.affiliation: National Institute of Physics, University of the Philippines, Diliman, Quezon City 1101, Philippines.
authors.forename: Raymund
authors.initials: R
authors.lastname: Sarmiento
authors.forename: Vernon Julius
authors.initials: VJ
authors.lastname: Cemine
authors.forename: Imee Rose
authors.initials: IR
authors.lastname: Tagaca
authors.forename: Arnel
authors.initials: A
authors.lastname: Salvador
authors.forename: Carlo
authors.initials: C
authors.lastname: Mar Blanca
authors.forename: Caesar
authors.initials: C
authors.lastname: Saloma