Precision at the Atomic Scale: PSU and KJLC Collaboration Earns JVSTA Editor’s Pick

Jeffrey R. Shallenberger of the Materials Research Institute at Penn State University has led a groundbreaking study demonstrating the detection of trace oxygen levels—down to 0.1 atomic percent—in highly reactive thin films using X-ray Photoelectron Spectroscopy (XPS). This work sets a new benchmark for precision in surface analysis and thin film quality control.

The study, “Detection of Low Levels of Oxygen in Reactive Materials by X-ray Photoelectron Spectroscopy (XPS),” was conducted in collaboration with Mr. Robert W. Hengstebeck (Penn State) and Dr. Gilbert B. Rayner (Kurt J. Lesker Company)¹. It addresses a critical challenge in the semiconductor and MEMS industries: the accurate measurement of oxygen and carbon impurities in non-oxide films such as titanium nitride (TiN) and aluminum nitride (AlN), where even minimal contamination can degrade performance.

Key to the study was quantifying the amount of trace gases inside the analytical chamber can elevate the reported oxygen and carbon values in XPS measurements. Jeffrey Shallenberger meticulous approach to experimental design and data interpretation enabled the team to overcome the inherent limitations of traditional XPS techniques. By carefully controlling vacuum conditions and acquisition timing, the team achieved reliable detection of oxygen at exposure levels as low as 0.1–0.2 Langmuir (L).

Jeff’s work exemplifies the precision and innovation needed to push the boundaries of materials analysis,” said Dr. Rayner. “His leadership was instrumental in developing a methodology that is both scientifically rigorous and practically applicable.

The research was made possible by the use of the Kurt J. Lesker Company ALD150LX atomic layer deposition system, equipped with their revolutionary Ultrahigh Purity Conditions (UHP-C) technology². This system provided the ultra-clean environment necessary to grow high-purity TiN and AlN films.

Picture of Kurt J Lesker ALD150LX

The findings offer a practical roadmap for researchers and manufacturers seeking to monitor and control impurity levels in thin films, ensuring optimal performance in next-generation electronic and optoelectronic devices.

References: 

1. Detection of low levels of oxygen in reactive materials by x-ray photoelectron spectroscopy (XPS)  :  https://doi.org/10.1116/6.0004652
2. Ultra-High Purity Conditions for Nitride Growth with Low Oxygen Content by Plasma-Enhanced Atomic Layer Deposition  :  jva20-ar-ald2021-00337.pdf
3. Kurt J. Lesker Company ALD-150LX: Designed for Advanced Research & Development Applications