Modern technologies have vastly benefitted from the miniaturised transducers developed in Micro-Electromechanical Systems (MEMS). Magnetic microdevices are one class of MEMS that demonstrate a significant potential for future applications in microrobotics, microfluidics, lab-on-chip, etc. For example, magnetic microfluidic chips can drastically reduce the costs and increase the throughput of DNA sequencing in genomic explorations and single-cell array analysis for cancer diagnosis. However, despite their great potential, the integration of magnetic material in microfabrication processes remains costly, time-inefficient and is therefore still an open research topic. For example, microtransducers manufactured by etching deposited layers have lower performance than bulk magnets of the same size. Even the most promising solutions for integrated magnetic materials in microfabrication processes, unfortunately deliver identical magnetic properties for the entire set of microdevices on a chip and cannot be individually tuned afterwards.
This project will develop a comprehensive solution to these problems. It will be delivered in three work packages (WP).
In WP1, this project will develop a new microfabrication process to realise on-chip programmable transducers in MEMS (p-MEMS). This process will integrate an array of magnetic microdevices with individual electrothermal microheaters. In this innovative technique the temperature of each microdevice increases in response to the applied electrical power to its corresponding heater. Applying an external magnetic field then produces the selective magnetic annealing. Therefore, exposing the entire magnetic microdevices on a chip to an external magnetic field and connecting selected heaters to electrical power will result in permanent magnetic changes only in the selected microdevices. Hence, this technique can develop various magnetic polarity patterns on a single chip by applying different combinations of external magnetic fields and selected heaters. WP1 will be carried out in close partnership with experts from BAE Systems who are particularly interested in the future micro and nano technologies.
In WP2, this research work will develop a new comprehensive micromagnetism model (M-MAG) to understand the magnetic behaviour of these microtransducers. The magnetic behaviour of thick microfabricated ferromagnetic (FM) layers in MEMS is different from thin films and bulk magnets. Thick layers are different from bulk magnets due to their atomic ordering after deposition. They are also different from thin deposited layers whose thicknesses of a few atoms impose certain constraints and assumptions that are not necessarily valid for thick layers. The new M-MAG model will be used to develop a computer aided design (CAD) tool for integrating the magnetic behaviour of microdevices into the available three dimensional micromechanical modelling tools. This will provide the multiphysics finite element analysis for the design of future microtransducers in p-MEMS.
In WP3, a prototype microfluidic chip will be developed using the p-MEMS process to test and verify the reliability of the process as well as the accuracy of the M-MAG model and simulations in the new CAD tool. There is a wide variety of applications for p-MEMS. Focusing on microfluidic applications will extend the cross disciplinary benefits of the proposed technique beyond Engineering and Physics. Just as programmable electronic integrated circuits enabled a wider community of non-expert users, the proposed research on p-MEMS will lead to a broader usage of these transducers emerging among other disciplines such as Biotechnology and Chemistry. Hence, WP3 will apply feedback from various end-users including experts from iGenomix UK.
The p-MEMS design kit including the layer thicknesses, material properties and layout design rules as well as the M-MAG model and the CAD tool will all be made freely available on the project webs