Optoelectronic material analysis and device failure analysis using SEM cathodoluminescence

Abstract

This paper reports on a portable Cathodoluminescence (CL) system which was developed and its applications to optoelectronic material analysis and device failure analysis. The portable CL detector was made from a solid-state photodiode which was mounted onto a specimen stage adaptor. Its portability allows it to be retrofitted to practically any standard scanning electron microscope (SEM) chamber stage without requiring any modifications to the SEM. The CL detector system was used to investigate non-radiative material defects in light emitting diodes (LEDs). Panchromatic CL micrographs of a degraded GaAs0.72P0.28 LED and a AlGaAs epilayer grown by molecular beam epitaxy (MBE) containing various material defects are presented. A case study on the application of the SEM CL mode to the failure analysis of extra junctions in a LED device is also presented. The CL micrographs indicated the presence of an anomalous p-n-p-n structure which was verified by the current-voltage (I-V) characteristic. © 1994.