Surface channel technology (SCT) was invented at the MESA+ institute almost 10 years ago and has opened the way for many new microfluidic devices. Most notably, it was the technology that allowed fabrication of a micro Coriolis mass flow sensor, which is the most sensitive Coriolis mass flow sensor to date and which is currently being commercialized by Bronkhorst High-Tech BV. The technology has some unique features:

• It allows the realization of flow channels with almost circular cross-section embedded in a silicon chip.
• The essentially circular cross-section results in very low pressure drop compared to surface micromachined channels.
• The tube material, silicon nitride, is highly inert and acceptable for most applications.
• The flat top of the channel allows the integration of actuation and readout structures.

Still, after 10 years of gradual improvements, the SCT technology has some important limitations in the dimensions of the resulting channels: at the lower end the wall thickness is currently limited to at least 1.3 μm (due to lithography limitations), and at the other end of the scale the maximum channel diameter is limited to about 80 μm (due to etching and deposition limitations). Furthermore, larger diameters tend to deform under pressure because the cross-section is not circular. We are now in the unique position, as the inventors of the original technology and with other groups just picking up on this technology, to open up routes for further miniaturization as well as allowing larger channel diameters. Extending the design freedom will undoubtedly result in many new developments. So far, we succeeded in making tube diameters ranging up to 80 microns, so, we need to develop a different technology to realise flow tubes with diameters ranging from 80 – 1000 microns, with a perfect circular diameter to withstand high pressures and pressure variations. Objective 2: Realize two technology demonstrators, one for very large and one for very small channel diameters. Realization of the two demonstrators will be the responsibility of the other PhD student. The following demonstrators are envisioned: a micro Coriolis mass flow sensor with a tube diameter of 500 μm which would find immediate application in the semiconductor industry, and a resonant sensor with a tube diameter below 1 μm which could be used for density measurement of gases or buoyant mass measurement of cells. Furthermore, since the flows to be measured are in some cases smaller than the existing measurement standards, calibration strategies, methods and equipment specifically suited for these low flow ranges need to be developed as well, in close cooperation with Bronkhorst and national metrology institutes such as VSL. You will work together with another PhD student who is responsible for developing the technology.

Your profile: We are seeking a highly motivated person with an excellent background in electrical engineering, applied physics, chemical technology, nano technology or closely related areas. You enjoy communicating your work verbally and in writing. You like working in a team, your curiosity inspires progress and you have clear scientific communication skills. We prefer applicants with strong English language proficiency. A scientific presentation can be part of the interview process.

Contact details: prof.dr.ir. J.C. Lotters: j.c.lotters@utwente.nl dr.ir. R.J. Wiegerink: r.j.wiegerink@utwente.nl

We want you to play a key role in an ambitious project in an inspiring international environment. We strive for diversity and fairness in hiring - we offer you a full time four-year position. We provide excellent mentorship and a stimulating, modern research environment with world-class research facilities. You will benefit from a professional and personal development program and a green and lively campus, with lots of sports facilities and other activities.

You will have a full time employment contract for the duration of 4 years and can participate in all employee benefits the University offers. The gross monthly salary starts with € 2.222,- in the first year and increases to € 2.840,- in the fourth year of your employment. Additionally, the University of Twente provides excellent facilities for professional and personal development, a holiday allowance of 8%) and an end of year bonus of 8.3%. A high-quality training program is part of the agreement. The research has to result in a PhD thesis at the end of the employment period.

The University of Twente. We stand for life sciences and technology. High tech and human touch. Education and research that matter. New technology which leads change, innovation and progress in society. The University of Twente is the only campus university of the Netherlands; divided over five faculties we provide more than fifty educational programmes. We have a strong focus on personal development and talented researchers are given scope for carrying out groundbreaking research.

We are an equal opportunity employer and value diversity at our company. We do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status or disability status. Because of our diversity values we do particularly support women to apply.

The faculty of Electrical Engineering, Mathematics and Computer Science (EEMCS) comprises three disciplines that shape Information and Communication Technology. ICT is more than communication. In almost every product we use mathematics, electronics and computer technology and ICT now contributes to all of societies' activities. The faculty works together intensively with industrial partners and researchers in the Netherlands and abroad and conducts extensive research for external commissioning parties and funders. The research which enjoys a high profile both at home and internationally, has been accommodated in the multidisciplinary research institutes MESA+, CTIT and MIRA.