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Electro-Optic Materials – Interview with La Luce Cristallina

La luce cristallina
Alex Demkov is the head of the Materials Physics Lab at the University of Texas at Austin and co-founder of La Luce Cristallina (LLC) together with Agham Posadas.

Hello Alexander & Agham, what is the focus of your research team?
A&A: The team fluctuates between 7 and 10 people and the focus is the integration of functional oxides on semiconductors. We study and unlock the properties of these materials and improve their electrical and optical interfacing with standard semiconductor substrates.

How did you evolve into this interest?  
A&A: Many years ago, at Motorola Labs in Tempe AZ, we were working on high-k dielectrics for FETs (field effect transistors), and one of the systems we looked at was single crystal strontium titanate on Si. I cannot stop emphasizing that I was blown away by the contribution of Rodney McKee from ORNL (Oak Ridge National Laboratory) that taught us how to suppress the oxidation of silicon by dosing its surface with strontium metal. This motivated us to look into growing strontium titanate (STO) and barium titanate (BTO) on Si when I joined the University. This was the moment when a theorist’s career turned experimental. In collaboration with IBM in New York, we were working on ferro-electric materials for Ferro-FETs (ferro-electric field effect transistors) when the excellent optical properties of BTO films on Si were discovered, so we changed our focus once again.

And later to a businessperson, as the founder of LLC. What is your product?
A&A: LLC wants to be the leading producer for advanced semiconductor-integrated oxides. In a way, the counterpart to SOITEC for photonic wafers, for materials that have best-in-class electro-optical properties and fit to semiconducting manufacturing since they don’t contaminate the production lines. Currently we run a facility for 50 mm wafers at the university, and we plan to move to our own facility early next year. We think the sweet spot for production will be 8 inch or 200 mm wafers, but 50 mm will remain for customers that cannot handle 8 inch wafers.

And the company name?
A&A: The name of the company came up in combination with the lawyers. In English,it had to be a neutral, and I love Italian. It can be translated as “The Crystal Light”, the optical property of the materials we work with.

What else were the enablers of the company?
A&A: What helped was that the related patents from ORNL were expiring, and we were thinking offering functional oxides on silicon using STO buffers as a commercial product. At the same time, interest in BTO for optical communication and quantum computing was taking off. The final piece was the need to develop an epitaxial deposition method compatible with mass production, which we achieved using sputter deposition. Backed by our long experience in working with crystalline oxides on silicon, we could now produce several thick film wafers per day. With all the pieces in place, we decided that it was now time to form a company.

Who are the current customers of LLC?
A&A: We are talking to the research divisions of various optical communications companies and to different university labs working in this field in the US, Europe and Japan.

How do you split your work between LLC and your professorship?
A&A: While Agham now works entirely for La Luce, I am formally a consultant for the company. However, working 60 hours a week is not sustainable in the long run and we will likely adjust commitments once we have our own manufacturing facility up and running.

Finally, what do you do when you are not working?
Agham: playing Dungeons and Dragons or just hanging out. Alex: taking the dog for walks and playing tennis. Polariton wishes you to do that more often.

POL: Thank you again for your time and pleasant chat.

Interview by Stephan Koch.