PhD Micro-mechanics of ultra-thin free-standing multi-layer membranes (V35.3189)

PhD Micro-mechanics of ultra-thin free-standing multi-layer membranes

The Eindhoven University of Technology (TU/e) has the following vacancy PhD Student position Micro-mechanics of ultra-thin free-standing multi-layer membranes in MEMS ultra-sound transducers (V35.3189).
Faculteit Werktuigbouwkunde


A PhD vacancy is available in the Mechanics of Materials group led by Prof. Marc Geers ( The candidates will be co-supervised by Dr. Olaf van der Sluis, Dr. Johan Hoefnagels, and Prof. Marc Geers. This PhD project is part of the recently approved large European research project called POSITION-II (“A pilot line for the next generation of smart catheters and implants”) research project, led by Philips Electronics.

A pilot line for the next generation of smart catheters and implants (POSITION-II)

About 10% of the western population will at a certain stage in their life be taken to a cath-lab for angioplasty surgery (stent placement), treatment of an arrhythmia or a heart valve replacement. Fortunately, most of these interventions can be carried out using minimally invasive procedures that are assisted by a host of smart imaging and sensing catheters that are the “eyes and ears” of the surgeon directly at the point of intervention. Essential and life-saving as these smart instruments are, they are without exception manufactured using outdated and obsolete technology. Surprisingly, over the past decade there has been little to none innovation, while clinicians are asking for instruments with better functionality that are smaller, cheaper and easier to use. The main reason for the lack of innovation is that these instruments are manufactured using technological point solutions that on their own do not generate enough production volume to justify continuous innovation.

It is the ambition of the POSITION-II project to realize a breakthrough by the introduction of open technology platforms for: miniaturization, in-tip AD conversion, wireless communication, MEMS transducer technology and encapsulation. The project consortium consists of 45 partners (industry, academia and institutes) from 12 European countries.

PhD project: Micro-mechanics of ultra-thin free-standing multi-layer membranes in MEMS ultra-sound transducers

The performance, and in particular the frequency response and output pressure, of MEMS ultra-sound transducers, critically relies on the mechanical properties of the ultra-thin free-standing multi-layer membranes that generate the ultrasonic waves. Currently, fundamental manufacturing challenges arise for frequencies above 40 MHz. Due to the high voltage driving conditions, reaching the fracture strength is not exceptional. This results in an undesired loss of functionality. In addition, residual stresses arise during manufacturing and result in performance changes as well as premature cracking or buckling of the films, which compromises the manufacturability and device performance. It has become clear that these multi-layer membranes push our understanding of ultra-thin film behavior to the limits. In order to enable the manufacturability of the next generation ultra-high frequency MEMS ultra-sound transducers, the micro-mechanics of the ultra-thin free-standing multi-layer membranes need to be better understood and controlled. To this end, this PhD project will establish the relation between the manufacturing of the free-standing membranes and the resulting residual stresses and thermo-mechanical properties, by means of a combined numerical/experimental multi-scale approach that incorporates the development of numerical models including size effects, and the experimental testing of dedicated in-line test structures that are processed by the project partners. 

Research group Mechanics of Materials

The PhD project is hosted by the Research group Mechanics of Materials at Eindhoven University of Technology ( The scientific research activities concentrate on the experimental analysis, theoretical understanding and predictive modelling of a range of phenomena in engineering materials at different length scales, which emerge from the physics and the mechanics of the underlying multi-phase microstructure. The main challenge is the accurate prediction of the thermo-mechanical properties of materials with complex microstructures. This focus is closely related to intrinsic material properties, the application of materials in microsystems and various systems and processes involving mechanically complex interfaces. The aim is a substantial increase of the predictive power of state-of-the-art models, thereby enabling the optimization of critical, high-tech products and manufacturing processes in direct relation to the complex loading history of the underlying materials. A systematic and integrated numerical-experimental approach is generally adopted for this purpose.

The group has a unique research infrastructure, both from an experimental and computational perspective. The Multi-Scale Lab allows for quantitative in-situ microscopic measurements during deformation and mechanical characterization within the range of 10-9-10-2 m ( In terms of computer facilities, several multiprocessor-multi-core computer clusters are available, as well as a broad spectrum of in-house and commercial software.


Talented, enthusiastic candidates with excellent analytical skills and high grades are encouraged to apply. An MSc degree in Mechanical Engineering, Physics, Materials Science, or a related discipline is required, as well as a strong background in continuum mechanics and computational methods. In particular, students with a specialization in micro-mechanics, thermo-mechanical material modelling, finite element techniques and/or experimental microstructural material characterization are encouraged to apply.


We offer:

  • a challenging job at a dynamic and ambitious university and in a world-class team
  • an appointment (1 fte) as a PhD-student for four years
  • gross monthly salary in accordance with the Collective Labor Agreement of the Dutch Universities (CAO NU), which favorably compares to conditions in the USA or UK.
  • an attractive package of fringe benefits, including excellent work facilities, end of the year allowance and sport facilities

Informatie en sollicitatie

Information and application
For more information on this PhD positions please contact Dr. Olaf van der Sluis ( and Dr. Johan Hoefnagels (

Application documents (in PDF format) must contain: letter of motivation, a detailed curriculum vitae, official transcripts of BSc and MSc grade lists and degrees, and contact information of at least two potential referees, including the main MSc supervisor.

As soon as possible. The vacancy is open until a suitable candidate has been found.