Huge lab, tiny structures

One of the largest laboratories for nanotechnology research in Europe lies right here in Delft; TNO's and TU's Van Leeuwenhoek Laboratory. It became fully operational last summer.

Not all overalls are equal. More experienced workers wear blue, like in this case Dr. Emile van der Drift. (Photo’s: Tomas van Dijk)

Yellow illumination in order to protect photo sensitive materials, a vibration-free floor, air with virtually no dust particles, staff wearing protective clothing from head to toe… and yes, in the corner, a handyvac, just in case someone does manage to dirty the place.

Every possible precaution has been taken in the cleanroom that holds the electron beam pattern generator (EBPG), a lithography machine that creates patterns just ten nanometers wide on chips. 
This four-million euro machine in TU Delft’s nanotechnology facility runs for 5,000 hours per year. “That corresponds to 13 or 14 hours a day, including New Year’s Eve and Christmas,” says Dr. Emile van der Drift, head of TU Delft’s section of the VLL. “It shows how important this machine is. We are here at the heart of all nanotechnology.”

Seated behind the computer that controls the EBPG are PhD students Georg Goetz and Wei Tang, from the quantum transport section (faculty of Applied Sciences). While Goetz is entering Linux codes to program the EBPG writing process, Tang is making notes on special dust-free cleanroom paper. “It’s really simple”, says Tang. “If you follow the recipe nothing can go wrong.”
The two PhD students are making a chip in order to study the electrical properties of quantum dots defined in carbon nanotubes. They are among the first users of the facility. First they let the lithography machine draw specific patterns with its electron beam on a film-coated silicon chip, and then they remove the exposed regions of the film, turning them into contact electrodes by evaporating metal on them. Finally they use a technique called chemical vapor deposition to grow carbon nanotubes between the contacts.
It’s for fabrication of test instruments – like this quantum dot for example, or nanoscale resonators that oscillate at high frequencies - that researchers, many of whom PhD students, come to this new facility. Van der Drift: “They’re building prototypes of functional nanostructures that will allow them to measure signals from complex phenomena that are hard to interpret.”
About 180 researches from TU Delft are now regularly using the Van Leeuwenhoek Laboratory, which in total consists of 6,000 m2 of laboratory space and 3,000 m2 of cleanroom.

Approximately forty people can work simultaneously in the section reserved for TU Delft researchers, who, previously, had conducted their nanotechnology research in the laboratories of the renowned Delft Institute of Microsystems and Nanoelectronics (Dimes). But 15 to 20 nanoresearchers were the maximum those laboratories could accommodate, so extra space was sorely needed.

Goetz: “Here we have more instruments; for instance an extra electron microscope and extra dry etching machines. And there is more space. Quite an improvement.”