Low-cost, high performance capacitors
Capacitors, electronic devices that store energy, are particularly important in electronic devices. For example, approximately 80 % of the surface of the integrated circuit of a mobile phone is devoted to single passive components, particularly capacitors. The ‘Monolithic above in ultra high value capacitors for mobile and wireless communication systems’ (Camelia) project was developed to respond to the technology integration challenge requiring more and more capability while using up less and less space. The researchers set out to fabricate thin film capacitors on-chip (as part of the microchip) enabling the delivery of high frequency decoupling capacitors with significant space savings and performance superiority compared to discrete chip capacitors (those as a separate component). The researchers investigated two types of ceramic materials in their search for the appropriate one with which to make thin ceramic films for high performance capacitors. The materials of choice were calcium copper titanate (CCTO) and lead zirconate titanate (PZT). Although PZT capacitors are not regulated, given the health hazards of lead the researchers sought to optimise use of lead-free CCTO. The team conducted numerous experiments to characterise materials and deposition methods with a focus on producing a high dielectric constant, the value associated with the ability of a capacitor to store charge or, in essence, do its job. The final outcome was the integration of high dielectric capacitors with a pacemaker in collaboration with an industrial partner, demonstrating a novel low temperature, high dielectric material technology for future high density or ultra low profile metal/insulator/metal decoupling capacitor applications. In summary, the Camelia project contributed valuable knowledge and technology to the field of low-cost, high performance thin film on-chip capacitors. Given the ubiquitousness of capacitors in electronic devices and the growing need for a new generation of capacitors such as the ones developed for the Camelia project, the outcomes could significantly enhance European competitiveness in the wireless electronic devices market.
