Probe detectors for mapping manufacturing defects

Abstract

The process-dependent defectivity of p-n junctions was investigated through the measurement of the avalanche triggering rate of single-photon avalanche diodes used as process probes. A nonlinear dependence of the ignition rate with the area of circular junctions is reported, which can be ascribed to a nonuniform density of the thermal generation centers, due to gettering. This has been verified by means of microscopic inspection and comparison with other available data. Technological hints are finally derived to counteract this nonuniformity.