Modeling the Electrical Degradation of Micro-Transfer Printed 845 nm VCSILs for Silicon Photonics

This article deals for the first time with the electrical degradation of novel 845 nm vertical-cavity silicon-integrated lasers (VCSILs) for silicon photonics (SiPh). We analyzed the reliability of these devices by submitting them to high current stress. The experimental results showed that stress induced: 1) a significant increase in the series resistance, occurring in two separated time-windows and 2) a lowering of the turn-on voltage. To understand the origin of such degradation phenomena, we simulated the I-V characteristics and the band diagrams by a Poisson-drift-diffusion simulator. We demonstrated that the degradation was caused by the diffusion of mobile species capable of compensating the p-type doping. The diffusing species are expected to migrate from the p-contact region in the top distributed Bragg reflector (DBR) towards the active layers.