Transition and Rare-Earth Metal Oxide Ultrathin Films for Energy-Efficient Wide Bandgap Semiconductor Devices
- UM Research
- 6 days ago
- 3 min read
Updated: 10 hours ago
Metal oxides combine metals with oxygen to create gate dielectrics with unique properties on semiconductor wafer substrates. Widely used in electronic devices such as transistors and sensors, metal-oxide-semiconductor (MOS) technology is crucial in modern electronics, including computers and smartphones.
As electronic devices become more powerful and compact, the materials used in their construction face new challenges. Traditionally, silicon dioxide (SiO₂) has been used as an insulating layer in these devices. However, as components become increasingly smaller, SiO₂ becomes less effective, leading to unwanted electrical currents, known as leakage current, that can impair device performance.
To address this issue, researchers are exploring various strategies to overcome the limitations of conventional silicon-based electronics. Prof. Ir. Dr Wong Yew Hoong, an expert in nanomaterials and semiconductor technology, leads this innovative research. He heads the Electronic Materials Laboratory and the Semiconductor Thin-Film Laboratory in the Department of Mechanical Engineering, Faculty of Engineering, at the Universiti Malaya (UM).
Prof. Wong and his team have been exploring alternative materials to silicon oxide, such as zirconium oxide (ZrO₂) and holmium oxide (Ho₂O₃). By layering these materials, they aim to create more effective insulating structures that efficiently manage electrical currents. They also focus on fine-tuning the manufacturing process, such as adjusting gas mixtures during production to enhance material quality and reliability. Additionally, the team addresses challenges like heat resistance, material defects, and electrical charge issues to develop durable semiconductors outperforming traditional silicon-based ones.
Prof Wong’s team discovered that the ZrO₂/Ho₂O₃ bilayer structure significantly reduced leakage current from 0.001 A/cm² for Ho₂O₃ to 0.000001 A/cm² for ZrO₂. Improved chemical bonding, specifically Zr–O–Si and Ho–O–Si, contributes to a bigger band gap in these materials, enhancing chemical stability and device longevity. It was also discovered that using equal parts of oxygen and nitrogen gas (50% each) during the deposition process yielded the best performance, due to improved interface quality. These advancements support the development of robust wide-bandgap (WBG) semiconductor devices, which are essential for energy-efficient, high-power electronics.
The development of ZrO₂/Ho₂O₃ bilayer material marks a significant step forward in addressing the physical and electrical limitations of traditional SiO₂-based devices. By combining the complementary properties of these materials and optimising interface quality by adding nitrogen (known as nitridation), the study demonstrates the potential for achieving energy-efficient and high-performance WBG semiconductor devices.
Commenting on future research directions, Prof. Wong and his team aim to explore other rare-earth oxides (REOs) to enhance performance while addressing the challenge of ensuring compatibility among ZrO2, Ho2O3 and the substrates, thereby preserving desirable electrical properties.. Enhancing thermal stability to mitigate defects and charge trapping is also crucial, especially for high-temperature applications, where maintaining stability is challenging. Collaborating with industry partners to integrate the bilayer structure into device prototypes for real-world testing will be essential; however, optimising interface quality requires carefully balancing gas mixtures during production. Additionally, the research will focus on sustainable fabrication techniques to reduce energy consumption and environmental impact.
In conclusion, this research underscores the significance of innovative material design and process optimisation in advancing the next generation of MOS technologies. The findings also lay the groundwork for future research on rare-earth oxides and their applications in sustainable and energy-efficient electronic devices.
Researchers Featured:
Prof. Ir. Dr Wong Yew Hoong
Department of Mechanical Engineering
Faculty of Engineering, Universiti Malaya
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Author:
Ms Farah Hannan Abd Nasir
A PhD student from the Physics Department who’s eager to blend science and storytelling - my goal is to make science relatable and exciting for everyone. When I’m not researching organic electronics, I enjoy playing the viola and painting with watercolours.
Copyedit:
Siti Farhana Bajunid Shakeeb Arsalaan Bajunid, Assistant Registrar, UM
Nurhazrin Zanzabir, Assistant Administrative Officer, UM
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