Furthermore, this method is in all honesty highly laborious says Mackus’ supervisor Erwin Kessels from Eindhoven University of Technology: ‘Imagine you were to build a house in this manner. Then you would build a complete cube of bricks and then subsequently remove the majority of those bricks with the exception of the walls. We are searching for ways of simply building just the walls for the structures and chips.’
In his NanoNextNL project PhD researcher Adrie Mackus combined two existing techniques to directly write patterns on the surface. With an electron beam he first wrote thin lines of platinum. The beam of electrons was targeted at gaseous platinum compounds that were scattered across the surface. Only the platinum particles located in the path of the beam were deposited on the surface. Next he used a technique called atomic layer deposition (ALD) to build walls of platinum on top of the lines. Atomic layer deposition uses gases to be able to deposit materials atomic layer by atomic layer on top of pre-defined locations. Up until Mackus’ research this method was mainly used to deposit complete films of materials and not so much for making thin lines.
Using a combination of techniques, Adrie Mackus managed to write neat electrical contacts of just a few micrometres in size directly on a surface.
Due to the major breakthrough that Mackus has managed to achieve with his approach he received his doctorate cum laude in 2013. Since then he has been a postdoc at the prestigious Stanford University. Meanwhile the researchers in Eindhoven have been working further on refining the technology, says Kessels: ‘With this technique you can make platinum contacts on chips but you can also build other nanostructures. If you want to make components with new materials such as graphene then, in principle, such a writing process works better than lithography. An approach such as that of Adrie combines the best properties of the two techniques used. And although I do not want to pretend that we have now found the final solution, I nevertheless have high expectations for it.’
NanoTextNL 2014, page 12
News item promotion Adrie Mackus
Thesis Adrie Mackus
Theme 9: Nano fabrication
Original author: Anouck Vrouwe