This work modifies existing nondestructive, laser-based techniques, such as thermally-induced voltage alteration (TIVA) and light-induced voltage alteration (LIVA), to determine precursors to failure in green and UV LEDs. Both TIVA and LIVA have been shown to be effective tools in localizing defects in Si-based integrated circuits and GaAs vertical cavity surface-emitting lasers. In a previous work, TIVA was also used to demonstrate failed InGaN LEDs in the III-V material system. This article expands the use of these techniques to localize potential precursors that lead to premature failures in deep green and deep UV LEDs. The paper shows how the TIVA/LIVA techniques were successfully used to characterize defects in wide bandgap AlGaN- and InGaN-based LEDs. The defects in the green LEDs appear to be electron-hole pair recombination sites and the observed voltage signals are primarily due to a LIVA effect.

Transmission electron microscopy (TEM) [1] and scanning capacitance microscopy (SCM) [2] have become common failure analysis tools at Sandia for new product development, process validation, and yield enhancement. These two techniques provide information that cannot be obtained with other analytical techniques. The information provided by these two techniques has been instrumental in identifying the root causes of several yield-limiting defects in CMOS IC technologies at Sandia. This paper describes an example of how TEM and SCM have been used to identify the root causes of SOI device failures. The corrective actions taken to reduce defects and improve yield are also described.