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The winning picture - an optical image of HfO2 thin film on n⁺⁺ Si substrate

The team comprising Thathsara Maddumapatabandi, Wei Fu, Fabio Bussolotti and Johnson Goh from the Quantum Innovation Centre (Q.InC) of A*STAR have been crowned the winners of the ‘AMP Image of the Month’ competition for July 2024 organized by A*STAR Microscopy Platform (AMP)!

Hafnium oxide (HfO2) is a well-known dielectric (insulator) used in the scaling of modern semiconductor electronics based in silicon. Its advantages in having a high dielectric constant, low current leakage and thermal stability are favourable for the development of more compact and efficient electronics.

To harness these advantages of hafnium oxide for a new class of two-dimensional semiconductors (e.g. transition metal dichalcogenides), a radical rethinking of the process technologies is required. The good compatibility of hafnium oxide with silicon enables its integration into existing foundry processes without major process redesign. In contrast, the existing process technologies for silicon device processing are not readily compatible with the more fragile nature of 2D semiconductors.

Johnson Goh’s team at Q.InC is developing the technology to utilise hafnium oxide on 2D semiconductor devices with the potential for realising next generation ultrascaled electronics for applications such as energy-efficient computing and quantum information processing. In a collaboration with Professor Joel Molina from the National Institute of Astrophysics, Optics and Electronics (Mexico), his team was investigating the possibility to integrate high quality foundry grown hafnium oxide thin films with the processing of 2D semiconductors. A very crucial initial step was to determine the thermal stability of the hafnium oxide film at the processing temperatures of typical 2D semiconductors and to carefully characterize its morphology change.

“In a series of samples that showed significant morphological changes, we consistently found these concentric defects that glow beautifully under the optical microscope. These “star” defects, as the team calls it, became a quick way to screen for such altered hafnia films simply with a normal optical microscope.”, said Thathsara who led this study.

“In research, as in life, it is easy to overlook the failures and only highlight the successes. Oftentimes, the path to success is fraught with multitudes of such “star” defects that point us back to the right direction.”, said the Principal Investigator Johnson Goh.

This month, one such “star” defect has been crowned the winner for the “AMP Image of the Month” contest for July 2024, and it will also be featured in the annual calendar design for FY25!

Congratulations to the team even as they persevere toward the goal of integrating hafnium oxide into 2D semiconductors. While others take time to smell the roses, let’s take a moment to catch a glimpse of the stars. This one for A*STAR!