Photonic Integrated Circuits (PICs) combine optical and electrical components on the same chip. While PICs enable faster, more compact and efficient optoelectronics, their fabrication can get tricky. For example, the lattice mismatch between Si and the III-V elements constituting the optical components results in lattice defects such as dislocations, which degrade the PIC performance.
In order to understand the mechanisms of the on-chip laser performance degradation and find the ways to avoid it, researchers from imec and Fraunhofer Institute for Microstructure of Materials and Systems IMWS looked into the electron-beam-induced-current (EBIC) response to electrical stress. They compared the devices stressed inside and outside of SEM with the signal from unstressed devices.
The results established that the performance degradation is indeed due to the electrical stress, and not other factors like carbon contamination or changes in contact resistance. These experiments have also pinpointed the areas where the failure occurs.
In this experiment, our probes were used to measure the IV characteristics of the device as well as to run the EBIC experiment and to systematically stress the device inside the SEM. The EBIC signal was collected and analyzed using the point electronic setup.
"The in-situ stress with consecutive EBIC measurements provides a better resolution for analyzing the impact of the electrical stress which shows that the nanoprobing technique can be applied as a useful methodology for localizing defects in nano-scale photonic devices," conclude the authors.
The exact failure mechanism will require further investigation, so we are looking forward to the next steps.