A novel laser slicing technique for diamond semiconductors

Focusing the energy of a laser beam into a small volume of a diamond sample creates tiny ‘modified regions.’ If these modified regions are laid out in a precise grid-like pattern, the ensuing cracks make it easy to separate a {100} wafer from the diamond.
Credit: Hirofumi HIDAI from Chiba University

The new technique uses laser pulses to slice diamond into thin wafers, paving the way for its adoption as a next-generation semiconductor material.

Silicon-based materials are currently the undisputed leaders in the field of semiconductors. Even so, scientists around the world are actively trying to find superior alternatives for next-generation electronics and high-power systems. Interestingly, diamonds are among the most promising materials for applications such as fast telecommunications and power conversion in electric vehicles and power plants.

Despite their attractive properties for the semiconductor industry, the applications of diamonds are limited due to the lack of techniques to slice them into thin wafers efficiently. As a result, diamond wafers must be synthesized one by one, making fabrication costs prohibitive for most industries.

Now, a research team from Japan, led by Professor Hirofumi Hidai from the Graduate School of Engineering at Chiba University, has found a solution to this problem. In a recent study, made available online on May 18, 2023, and published in Diamond & Related Materials in June 2023, they report a novel laser-based slicing technique that can be used to cleanly slice a diamond along the optimal crystallographic plane, thus producing smooth wafers. Their study is co-authored by master’s student Kosuke Sakamoto from the Graduate School of Science and Engineering at Chiba University and former Ph.D. student Daijiro Tokunaga, currently an Assistant Professor at Tokyo Institute of Technology.

The properties of most crystals, including diamonds, vary along different crystallographic planes—imaginary surfaces containing the atoms comprising the crystal. For instance, a diamond can be easily sliced along the {111} surface. However, slicing {100} is challenging because it also produces cracks along the {111} cleavage plane, increasing kerf loss.

To prevent the propagation of these undesirable cracks, the researchers developed a diamond processing technique that focuses short laser pulses onto a narrow cone-like volume within the material. “Concentrated laser illumination transforms diamond into amorphous carbon, whose density is lower than that of diamond. Hence, regions modified by laser pulses undergo a reduction in density and crack formation,” explains Prof. Hidai.

By shining these laser pulses onto the transparent diamond sample in a square grid pattern, the researchers created a grid of small crack-prone regions inside the material. If the space between the modified regions in the grid and the number of laser pulses used per region are optimal, all modified regions connect to each other through small cracks that preferentially propagate along the {100} plane. Consequently, a smooth wafer with {100} surface can be easily separated from the rest of the block by simply pushing a sharp tungsten needle against the side of the sample.

Overall, the proposed technique is a pivotal step toward making diamonds a suitable semiconductor material for future technologies. In this regard, Prof. Hidai remarks: “Diamond slicing enables the production of high-quality wafers at low cost and is indispensable to fabricate diamond semiconductor devices. Therefore, this research brings us closer to realizing diamond semiconductors for various applications in our society, such as improving the power conversion ratio in electric vehicles and trains.

Let us hope that this coveted crystal gives us an edge in our quest for advanced technological development, including those that can ensure a more sustainable future!

 

About Professor Hirofumi Hidai

Hirofumi Hidai obtained his doctoral degree from Tokyo Institute of Technology in 2004. He joined Chiba University in 2010, where he currently holds the title of Full Professor at the Department of Mechanical Engineering. His research interests lie mainly in advanced manufacturing technologies, including precision machining and laser-based processing. He has published over 100 papers on these topics and holds three patents. He is also a member of the Laser Society of Japan, the Japan Society of Applied Physics, and the Japan Society for Precision Engineering, among others.

Journal: Diamond and Related Materials
DOI: 10.1016/j.diamond.2023.110045
Method of Research: Experimental study
Subject of Research: Not applicable
Article Title: Laser slicing of a diamond at the {100} plane using an irradiation sequence that restricts crack propagation along the {111} plane
Article Publication Date: 18-May-2023
COI Statement: The authors declare the following financial interests/personal relationships, which may be considered potential competing interests: Noboru Morita reports financial support was provided by the New Energy and Industrial Technology Development Organization and Japan Society for the Promotion of Science. Takashige Omatsu reports financial support was provided by Japan Society for the Promotion of Science and the Japan Science and Technology Agency. Hirofumi Hidai reports financial support was provided by the Japan Science and Technology Agency and the Machine Tool Engineering Foundation and has a patent to be submitted pending to Chiba Univ & Orbray Co. Ltd. Daijiro Tokunaga reports financial support was provided by the Japan Science and Technology Agency.

Media Contact

Momoko WATANABE
Chiba University
momoko_watanabe@chiba-u.jp

Expert Contact

Hirofumi HIDAI
Graduate School of Engineering, Chiba University
hidai@faculty.chiba-u.jp

Media Contact

Momoko WATANABE
Chiba University

All latest news from the category: Materials Sciences

Materials management deals with the research, development, manufacturing and processing of raw and industrial materials. Key aspects here are biological and medical issues, which play an increasingly important role in this field.

innovations-report offers in-depth articles related to the development and application of materials and the structure and properties of new materials.

Back to home

Comments (0)

Write a comment

Newest articles

Innovative 3D printed scaffolds offer new hope for bone healing

Researchers at the Institute for Bioengineering of Catalonia have developed novel 3D printed PLA-CaP scaffolds that promote blood vessel formation, ensuring better healing and regeneration of bone tissue. Bone is…

The surprising role of gut infection in Alzheimer’s disease

ASU- and Banner Alzheimer’s Institute-led study implicates link between a common virus and the disease, which travels from the gut to the brain and may be a target for antiviral…

Molecular gardening: New enzymes discovered for protein modification pruning

How deubiquitinases USP53 and USP54 cleave long polyubiquitin chains and how the former is linked to liver disease in children. Deubiquitinases (DUBs) are enzymes used by cells to trim protein…