MSE is pleased to announce that Dongjae Shin, a third-year Ph.D. student in the Li group, recently received the Helen & Rolf Illsey Scholarship from the Society of Vacuum Coaters Foundation (SVCF). Shin is conducting research focused on vacuum deposition technologies, the findings from which could revolutionize applications in batteries, memories and synaptic transistors.

Vacuum deposition technologies are crucial for manufacturing microelectronic devices and play a significant role in high-technology development. In his research, Shin deposited metal oxide films that are nanometers thick and investigated their mass transport properties. He discovered that as-deposited metal oxide thin films tend to be metastable amorphous phases, exhibiting different properties in terms of ion transport. To understand the governing rule of ion transport in amorphous metal oxides, he chose amorphous hafnium oxide thin films as a model material. His findings revealed that sub-stoichiometric amorphous hafnium oxide has lower oxygen tracer diffusion than stoichiometric amorphous hafnium oxide, and amorphous hafnium oxide thin films with higher density show slower diffusion. These results contradict the diffusion trend observed in crystalline hafnium oxide. These findings were applied to hafnium oxide-based resistive memory devices, demonstrating that the device information retention time equals the characteristic oxygen diffusion time. This result indicates that thin film deposition processing conditions can control ion transport, affecting device performance and reliability. His research suggests new design rules and classifications for amorphous ionic conductors, emphasizing density and free volume as key considerations for ion transport in amorphous materials, which could revolutionize applications in batteries, memories, and synaptic transistors.

Congratulations, Dongjae!