High-sensitivity photodetectors with on-chip pinhole for laser scanning microscopy

We manufactured new high-sensitivity solid-state detectors, specifically designed for measurements in laser scanning microscopy (LSM). These single-photon avalanche diodes (SPAD's) improve the performance achievable with an LSM apparatus in the optical inspection of microelectronic devices and circuits. Innovative detector structures that incorporate an on-chip pinhole filter are presented. Experimental measurements show that SPAD's perform better than standard photomultiplier tubes.