Extraction of bonding strain data in diode lasers from polarization-resolved photoluminescence measurements

A technique to determine strain in diode lasers by matching measured polarization-resolved photoluminescence to a finite element method model is described. The code is shown to be able to fit well a finite element model with degree of polarization measurements to extract strain information from diode lasers and predict strain values owing to die bonding. It is useful in characterizing die bonding processes and in detecting solder voids which can impact the reliability of devices. Using the code, it is demonstrated that there are differences in the die bonding strain from different die attachments. The bonding strain from InP chips die bonded to copper and silicon chip carriers using gold–tin solder are examined.