High resolution thermoreflectance imaging on transistor arrays with defect-induced leakage

Abstract
Crystal defects are very harmful in present silicon devices when responsible for a source-to-drain junction piping and hence for a transistor leakage current. These effects are difficult to characterise with existing methods. Two transistor arrays including patterns critical for defect formation have been constructed and then characterised using a multiplexed CCD-based thermoreflectance microscope. Since this technique measures heating associated to defects, it does not discriminate dielectric breakdown and actual source-to-drain leakage. Both types of defects, buried under 6 m of intermetal and encapsulation dielectric, are clearly detected with a spatial resolution of 350 nm.