From Lebanon to Grenoble: a path driven by scientific curiosity
Originally from Lebanon, Georges Al Hoyek began his studies in fundamental physics in his home country before pursuing a Master's degree in nanoscience and nanotechnology in Rennes. This academic path, at the intersection of physics, chemistry, and microelectronics, naturally led him to a PhD at CEA-Leti.
He chose Leti both for its reputation for excellence in France and Europe and for its semi-industrial positioning:
“I wanted to work in an environment that is both academic and close to the industrial world. Leti perfectly represents this balance," he explains.
Georges presented his paper “Hydrochloric acid treatment of InP surfaces in N2-controlled atmosphere" at UCPSS, a major international event dedicated to ultra-clean manufacturing processes, where he won the Best Student Paper Award. He recalls the experience vividly:
“It was impressive to exchange with experts from Sony, Samsung, as well as researchers from the United States and Asia. These discussions give real perspective to our work."
A paper focused on the functionalization of InP surfaces
Georges' research focuses on the functionalization of InP (indium phosphide) surfaces, a semiconductor alternative to silicon that is particularly promising because of its optical and electronic properties. However, its use in microelectronics is hindered by a major challenge: the spontaneous formation of an oxide layer and organic contaminants on the surface of the material.
The objective of his work is to develop an efficient de-oxidation protocol within the framework of wet cleaning, a key step in surface preparation before integration into microelectronic devices.
“We are trying to understand where this oxidation comes from and how to control it in order to obtain a surface that is as clean and stable as possible," he explains.
To carry out his study, Georges developed and optimized a dedicated experimental setup assembled by the LTM (IMPACT platform), combining a glove box with a pARXPS 300 mm analysis system, both connected by a vacuum transfer system. He compares the effects of a wet chemical treatment performed under two atmospheres, air and nitrogen (N₂), followed respectively by transfer in air and under vacuum, in order to evaluate the impact of the environment on oxidation.
Using the pARXPS technique (parallel-angle-resolved X-ray Photoelectron Spectroscopy), he analyzes the chemical composition of the outermost surface layers with high precision. Observations following wet chemical treatment under nitrogen and vacuum transfer show that this treatment effectively removes oxides from the InP surface, whereas an InP substrate treated and transferred in air undergoes rapid re-oxidation. He also studied the re-oxidation kinetics of the InP surface, demonstrating that exposure to air for one minute or less of an already treated InP substrate prevents any significant re-oxidation of its surface.
Promising results for the microelectronics of the future
This work has direct applications for advanced microelectronics, particularly in the fields of silicon photonics and die-to-wafer integration, which explore substrates alternative to silicon.
Georges adds that “our protocols could be studied on other materials and integrated into the fabrication steps of future optoelectronic devices."
In the long term, the results could also be used for InP wafer bonding or for the fabrication of prototype transistors using alternative materials such as InP.