06/3 Thick films

		Examples of thick-film sensors: A) pressure cell - left: steel & right: "classical" alumina; B) steel tension force sensors and close-up of the thick-film sensing bridge; C) experimental force sensor on aluminium with very low-temperature thick-film technology; D) instrumented knee force sensor made out of special biomedical grade stainless steel.

We plan to adapt the "classical" strain-sensing thick-film piezoresistive technology to biomechanical applications. This has three main implications, which are the aims of this subproject:

• We must adapt / develop thick-film materials that are compatible with high-strength medical alloys such as stainless steels and titanium alloys. This implies a reduction of the "traditional" 850°C firing temperature to below ca. 600°C, in order to limit degradation of the metals by softening, phase transformation and/or oxidation.
  
• A longer-term task is to make progress in moving away from existing lead-based materials (which have to be very carefully shielded from contact with the patient) to environmentally and biologically more benign ones.
  
• Especially for implants, reliable packaging solutions have to be developed to avert degradation of the sensors in the human body and / or adverse body reactions to the sensors.