Singh Seminar Series: Brian Edward and Pedram Yousefian

Singh Center Seminar Series

Date: Thursday, June 26, 2025

Time: 12:00 pm

Singh Center – Glandt Forum

Talk 1: Thin Film Optical Metrology (Ellipsometry and Reflectometry)

Speaker: Brian Edwards

Reflectometry and Ellipsometry are essential optical metrology techniques widely used in nanofabrication for characterizing thin films and layered structures. This talk provides an introduction to the principles, instrumentation, and practical limitations of both methods. We will explore how Reflectometry leverages light intensity measurements and how Ellipsometry uses polarization changes. This session will highlight when and why to use each technique, their respective advantages and limitations, and best practices for integrating them into process monitoring and quality control workflows.

About the Speaker

Dr. Brian Edwards is an applied physicist with deep expertise in optical metrology and advanced instrumentation. He has about 20 years of experience designing RF and optical systems.

Talk 2: Leakage Suppression in AlScN Thin Film Ferroelectric Capacitors through Boron Incorporation

Speaker: Pedram Yousefian

This work demonstrates high-temperature ferroelectric characterization of 40 nm AlBScN thin film capacitors grown by co-sputtering Al0.89B0.11 and Sc targets onto Pt(111)/Ti(002)/Si(100) substrates. Structural analysis confirmed a c-axis-oriented wurtzite structure with a low surface roughness of 1.37 nm. Ferroelectric switching, characterized by positive-up-negative-down (PUND) measurements up to 600 °C, exhibited a linear decrease in coercive fields from 6.2 MV/cm at room temperature to 4.2 MV/cm at 600 °C, while remanent polarization remained stable with temperature. Direct current I–V measurements highlight a significant suppression of leakage currents, over two orders of magnitude lower compared to AlScN capacitors fabricated under similar conditions. These results position AlBScN thin films as strong candidates for ferroelectric applications in extreme environments.

About the Speaker

Pedram Yousefian received a B.Sc. in Materials Science and Engineering from Isfahan University of Technology, an M.Sc. in Mechanical Engineering from the University of North Florida, and a second M.Sc. in Materials Science and Engineering from Lehigh University. He completed his Ph.D. in Materials Science and Engineering at Penn State and joined the Olsson Group at the University of Pennsylvania as a postdoctoral researcher in July 2024.

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