
This thin diamond wafer is also very flexible
Nature, DOI: 10.1038/s41586-024-08218-x
A new method of using adhesive tape to create ultrathin diamond wafers could help make diamond-based electronics, and it may one day provide a useful alternative to silicon-based designs.
Diamond is an excellent insulator, and at the same time has unusual electronic properties that allow electrons with a certain energy to move with little resistance. This means it can handle high energy with higher efficiency than traditional silicon chip designs.
However, manufacturing practical diamond chips requires large, very thin wafers, similar to the thin silicon wafers used to make modern computer chips, which have proven difficult to create.
Now, Zhiqin Chu and colleagues at the University of Hong Kong have discovered a way to make extremely thin and flexible diamond wafers using adhesive tape.
Chu and his colleagues first embedded nano-sized diamonds in a small silicon wafer and then sprayed methane gas at high temperatures onto them to form a continuous, thin sheet of diamond. Next, I made a small crack on one side of the pasted diamond sheet, and then used regular adhesive tape to peel off the diamond layer.
They say that this exfoliated diamond sheet is extremely thin, less than a micrometer, much thinner than a human hair, and smooth enough to use the kind of etching techniques used to make silicon chips. I discovered.
“This is very reminiscent of the early days of graphene, when cellophane tape was used to fabricate the first monolayer of graphene from graphite. I never imagined this concept would be applied to diamond. ” says Julie McPherson of the University of Warwick, UK.
“This new edge-exposed delamination method will enable a large number of device designs and experimental approaches,” said Mete Atatüre from the University of Cambridge. One area that could be particularly useful is increasing control over quantum devices that use diamonds as sensors, he says.
Andrea Ferrari of the University of Cambridge said that the diamond films Chu and his colleagues were able to produce were about 5 centimeters in diameter, showing that the method could work as a proof of principle, but that they were still able to produce diamond films larger than 20 to 30 centimeters. It is said to be smaller than a centimeter. This is the standard for many wafer processes, he says, and it’s not clear whether the new method can be scaled up.
The manufactured wafers also appear to be polycrystalline, but they are not as smooth and regular as single-crystal diamond, which may limit their use in some applications, McPherson said.
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