PhD position on the monitoring of VCSEL and MJSC growth by molecular beam epitaxy at LAAS-CNRS.
Vertical-Cavity Surface-Emitting Lasers (VCSELs) and multijunction solar cells (MJSC) are composed of complex stacks of epitaxial layers, but they are well mastered, and today most of the technological barriers concerning their industrialization have been removed. The growth mechanisms are well known, but the production yield is still too low to meet the more demanding specifications of new growing markets such as LIDAR sensors or 3D detection. The wide deployment of VCSELs and MJSC is driving towards greater automation and real-time control of manufacturing methods, primarily epitaxy.
This thesis work will focus on the following developments:
- Implementation of real-time in-situ measurements for the epitaxy of AlGaAs and InGaAs alloys: curvature, reflectometry, RHEED, roughness measurements.
- Modeling to reproduce these optical and structural measurements
- Implementation of methodologies to control the growth of VCSEL and MJSC structures
- Manufacturing of VCSEL and MJSC devices in cleanroom and characterization of their performances
Within the framework of a joint laboratory (epicentre.cnrs.fr) between LAAS-CNRS and RIBER (world leader in the epitaxy equipment market), we aim to develop a set of complementary in-situ measurement tools, automated and controlling in real time the growth parameters by molecular beam epitaxy (MBE). This is to reduce the multiple drifts related to the complexity of the MBE growth process and thus to increase the production yield.