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Micromachined and optical systems using thin oxide films


The main aim of this programme is to increase and improve the functionality of micromechanical components by using the piezoelectric and pyroelectric properties of PZT thin films. To widen their range of applications these materials will be incorporated for the first time into a micromachined gyroscope, a piezoelectric pump, and an optical switch for a planar waveguide. A resonant thermal sensor,
incorporating PZT in a novel geometry, will also be developed.
The combination of recent technology developments in silicon micromachining with those in PZT thin film deposition provides an opportunity to realise a new range of miniature sensors. PZT processes will be optimised by studying the piezoelectric and pyroelectric properties of thin films deposited on materials and structures that will be used in the demonstrators. These results will be used as input for the demonstrator design. Different PZT deposition techniques will be optimised to produce both thin (<0.3 mm) and thick (>5 mm) films. Silicon micromachining techniques, including deep reactive ion etching, will be developed to produce resonating structures out of single crystal silicon with a high mechanical Q. For the thermal and optical demonstrators, electrodes will be developed that are both electrically conductive and optically transparent. Techniques of encapsulation and interconnection will be developed that allow the demonstrators to achieve the optimum performance permitted by this new technology.

The use of thin film piezoelectric material deposited on
micromechanical oscillating elements is an attractive means of simplifying device designs. The design of the gyroscope will benefit from the involvement of an end user, who will be able to provide information on the operating conditions; the performance of the thermal sensor and piezoelectric pumps will be assessed against more conventional structures. Significant performance advantages are expected. The application of PZT will allow fast, reliable and low power optical switching in a planar waveguide, providing a new component for existing and future broadband access optical networks.
Gyroscopic and thermal sensors are all undergoing rapid technological advance in response to the expanding market for compact devices. The market for micromachined gyroscopes in automobiles has been valued at 50MECU by the year 2006, and that for low priced thermal detectors at l00MECU.

The consortium of partners that has been brought together to achieve the goals of the programme includes four industrial companies involved in respectively the development and manufacture of systems for the laser crystallisation of materials, the development of sol gel ferroelectric thin films for integrated micromachined thermal arrays, the development of micromachined components for the automotive industry, and the design and manufacture of planar optical systems. They are supported by a research organisation with expertise in sol gel and hydrothermal deposition techniques. Two academic institutions, one with experience in the design and fabrication of miniature gyroscopes and the other having a wide range of both bulk and surface micromachining expertise, will be involved in the programme.
The main achievements of this programme will be the development of processes that allow PZT actuation and sensing in micromechanical devices. Processes available for encapsulation and interconnection will allow exploitation of the demonstrators.



Participants (6)

Corning SA - Centre Européen de Recherche de Fontainebleau
7 Bis,avenue De Valvins 7 Bis
77210 Avon
Im Stadtwald Gebauede 43
66123 Saarbruecken
Kungliga Tekniska Högskolan

100 44 Stockholm
Melexis NV
12,Rozendaalstraat 12
8900 Ieper
Société de Production et de Recherche Appliquée - SOPRA
26,Rue Pierre Joignaux 26
92270 Bois
United Kingdom
University Park
NG7 2RD Nottingham