~16 hours in cleanroom (Grenoble)

Techniques practiced: Optical lithography, plasma etching, metal deposition
Tools used: SEM, profilometers, wet benches
Projects: Passive waveguides, simple MOS structures, photovoltaic cell fabrication

Entering the cleanroom

During my second year at Phelma, I had my first hands-on cleanroom experience. Suited up from head to toe, I quickly realized how different it feels to work in such a controlled environment. It reminded me of the COVID period in some ways, but this time, the equipment wasn’t just for protection — it was a necessity to keep dust and particles away from nanostructures.

After the preparation, we visited the cleanroom and discovered the full range of equipment we had only seen in lectures: photolithography machines, etchers, deposition chambers, and microscopes. Seeing these tools up close for the first time was truly impressive.

From silicon to device

The goal of the training wasn’t just observation, but fabrication. Our task: to create a photovoltaic cell from a raw silicon wafer.

Step by step, we carried out:

  • Optical lithography to define patterns on the wafer.
  • Plasma etching to transfer those patterns into the material.
  • Metal deposition to form contacts.

Along the way, we also had the chance to fabricate simpler structures such as passive waveguides and MOS transistors, which gave us a broader sense of how the same core processes can serve very different applications.

(Insert picture of me in the suit here)

Characterization

A few weeks later, we brought our samples back to the lab for characterization. Using profilometers, scanning electron microscopes (SEM), and wet benches, we analyzed the structures we had built.

The photovoltaic cell worked — not very efficiently, but enough to demonstrate the entire process from design to measurement. Seeing light converted into electricity with a device we had made ourselves was both satisfying and motivating.

(Insert pictures of samples and characterization here)

Reflection

This short (~16h) cleanroom training gave me my first taste of nanofabrication, transforming theory into practice. It taught me not only the importance of precision and cleanliness, but also how diverse fabrication steps combine to produce functional devices.

Even though the final device was far from perfect, the experience confirmed my interest in working at the intersection of physics, materials, and technology.