Scientists have used a new method using graphene to reduce the costs of wafer technology. Devices are created from exotic, higher-performing semiconductor materials, not conventional silicon. Graphene uses graphite sheets created from single atoms. They are used as a kind of 'copy machine' to shift crystalline patterns from a semiconductor wafer to the topmost layer of identical material.
In 2016, before the use of graphene, that the annual global semiconductor sales touched their peak at $339 billion, according to SIA. The semiconductor industry spent $7.2 billion on wafers serving as substrates for microelectronics components. These can be transformed into transistors, light-emitting diodes, as well as similar electronic and photonic devices.
MIT engineers have devised a new technique based on graphene that can bring down the overall cost of wafer technology. They could also enable devices from exotic, high-performing semiconductor materials, instead of conventionally used silicon, according to ScienceDaily.
The engineers took up some carefully controlled techniques that could place single sheets of graphene on an expensive wafer. They grew further semiconducting material over the graphene layer. While the graphene was found to be thin and electrically invisible, it enabled the top layer to look through the graphene and see the underlying crystalline wafer. It could imprint patterns but not get too influenced by the graphene. The graphene is "slippery" without sticking to other materials too quickly, it also enabled the engineers to just remove the semiconducting layer from the top of the wafer after the structures were imprinted.
Jeehwan Kim, the Class of 1947 Career Development Assistant Professor in the departments of Mechanical Engineering and Materials Science and Engineering, pointed out that in a traditional semiconductor, the wafer's crystalline pattern would get transferred and then bond so closely to the semiconductor that it could not get separated without damage. "You end up having to sacrifice the wafer -- it becomes part of the device," Kim said. The novel method enables manufacturers to use graphene in an intermediate layer.
Through the method, scientists could use the graphene, copy and paste the wafer and then separate a copied film from the wafer. The scientists could then reuse the wafer a number of times. This was a novel method that could cut down on the cost of the wafers and also open a number of opportunities to explore exotic semiconductor materials.
"The industry has been stuck on silicon, and even though we've known about better-performing semiconductors, we haven't been able to use them, because of their cost," Kim says. "This gives the industry freedom in choosing semiconductor materials by performance and not cost."
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