Development of oxide thick film capacitors for a real time pressure monitoring system

Abstract Accurate pressure readings are essential tools in a wide range of applications. For example in monitoring intracranial pressure for patients with head injuries or tyre pressure to improve automobile safety. With this in mind, a real time monitoring system, which displays the change in sensor capacitance with pressure on a PC, has been developed. Thick film capacitors with an oxide dielectric layer formed using niobium pentoxide (Nb 2 O 5 ), titanium dioxide (TiO 2 ) and cerium dioxide (CeO 2 ) are investigated using this system. SEM was used to examine the morphology and particle size of the thick films. To aid in the development of a suitable interface circuitry, the frequency and temperature dependence of each device is investigated. Each sensor was then subjected to pressures in the region of 0–100 kPa. The results show that capacitors with an Nb 2 O 5 dielectric layer were most sensitive. It is thought that this is due to its particle size.

[1]  George J. Weng,et al.  A theory of compressive yield strength of nano-grained ceramics , 2004 .

[2]  Marcus Textor,et al.  Titanium in Medicine : material science, surface science, engineering, biological responses and medical applications , 2001 .

[3]  C.C. Liu,et al.  Fabricating biomedical sensors with thin-film technology , 1994, IEEE Engineering in Medicine and Biology Magazine.

[4]  Charles A. Harper.  Handbook of Thick Film Hybrid Microelectronics; A Practical Sourcebook for Designers, Fabricators, and Users. , 1974 .

[5]  S. Musić,et al.  Sol–gel synthesis and characterization of Nb2O5 powders , 2004 .

[6]  S. Dutta,et al.  Grain size dependence of optical properties and positron annihilation parameters in Bi2O3 powder , 2004, Nanotechnology.

[7]  N. White,et al.  Thick-film sensors : past, present and future , 1997 .

[8]  A Arshak,et al.  Review of the potential of a wireless MEMS and TFT microsystems for the measurement of pressure in the GI tract. , 2005, Medical engineering & physics.

[9]  Stergios Logothetidis,et al.  Enhanced catalytic activity of nanostructured cerium oxide films , 2003 .

[10]  Khalil Arshak,et al.  Investigation of TiO2 thick film capacitors for use as strain gauge sensors , 2005 .

[11]  Robert Puers,et al.  Capacitive sensors: When and how to use them☆ , 1993 .

[12]  O. Korostynska,et al.  Evaluating the suitability of thick-film TiO2 capacitors for use in a wireless pressure measurement system , 2006 .

[13]  Khalil Arshak,et al.  Development of new capacitive strain sensors based on thick film polymer and cermet technologies , 2000 .