Silicon deformable mirror for optical communications and astronomy

The Flexible Electronics Department (FEL) in Gardanne is part of the Provence Microelectronics Centre (CMP), one of the five research centers of Mines Saint-Etienne, itself a School of the Institut Mines Telecom. Its skills include flexible and stretchable electronics, heterogeneous integration, energy harvesting and flexible batteries.The department's research is motivated by developing autonomous and communicating electronic systems for the design of sensitive interfaces, electronic skin, medical devices, etc

Significant progress in the field of optical telecommunications and astronomy were achieved these last decades thanks to the control of optical aberrations using active shape mirror technology. Yet, commercial mirror technologies are still suffering from fragility, temporal bandwidth, dynamical range, and size limitations and their cost. We aim to develop a new lightweight, hybrid, high-speed mirror technology based on state-of-the-art processes to fabricate a self-supporting and defect-free silicon membrane, as well as to develop 3D printed electroactive polymer actuators.
In this context, the transfer of the silicon membrane to 3D printed pillar actuators is a critical step. Indeed, a thin silicon membrane can be easily deformed and even broken during handling and attachment to the pillars. When
handling membranes less than 100 microns thick, the use of a temporary support will likely be necessary.
The objective of this internship is to study and optimize the handling and transfer process of thin silicon membrane onto pillars using both simulation software and experimental procedures.
Description :
The master student will first carry out a bibliographical study in order to draw up a state of the art on the various technologies of temporary bonding of an holder on a thin silicon membrane.
In parallel, the trainee will develop the modeling of the attachment of a thin silicon membrane to pillars using COMSOL software. Finite Element Modelling (FEM) will be performed for investigating the stress relaxation strategies in Si membranes, and will be also deployed to characterize the mechanical deformation induced at the interface between the silicon membrane and pillars. The localization of regions of high stress and strain will allow to improve the transfer process by optimizing the design of the temporary support, the thickness of the silicon, the shape of the pillars and their distribution across the membrane surface.
Pillars will then be 3D printed on a rigid substrate and transfer experiments of the thin silicon membrane onto these pillars will be performed. The residual deformation of the membrane will be studied using interferometric measurements and finally compared to the simulation predictions.

The master fellow should have a background in materials science, mechanics or process technologies and have autonomy and good communication skills