Low Temperature (≪100°C) deposited pyrochlore films with high capacitance (200 nF/cm2), low loss (∼0.003) and low TCF (≪100 ppm/C) for integrating RF components

• Published in: 2008 58th Electronic Components and Technology Conference pp. 688 - 693
• Main Authors: Raj, P.M., Jin-Hyun Hwang, Hyung-Mi Jung, Kumar, M., Jha, G., Coulter, K., Wellinghoff, S., Iyer, M., Tummala, R.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.05.2008
• Subjects: Barium; Capacitance; Capacitors; Ceramics; Plastic films; Polymer films; Radio frequency; Substrates; Temperature; Titanium compounds
• ISBN: 9781424422302; 1424422302
• ISSN: 0569-5503; 2377-5726
• DOI: 10.1109/ECTC.2008.4550047

We demonstrate polymer ceramic composites and pyrochlore based thin film capacitors for embedded RF capacitors. Unlike perovskites such as barium titanate, pyrochlores have low loss and stable properties with temperature and frequency while retaining a moderately high dielectric constant. Hence, these are ideally suited for RF capacitor components both as fillers in polymers and as ultrathin films. Unfortunately, pyrochlores are generally formed at above 400 C making them difficult for organic compatible integration either on BCB build-up layers on Si or traditional organic substrates. In this report, we report new energy irradiation processes that can form pyrochlores at temperatures less than 100 C. The process starts by depositing a thin layer of Ti by e- beam evaporation, followed by hydrothermally converting it to barium titanate. The film is then converted into a pyrochlore phase at less than 100 C by oxygen ion irradiation. The phase transformation results were confirmed with XRD and SEM. By a combination of wet chemical treatment followed by oxygen ion irradiation, this technique shows the feasibility of depositing a low TCC (<100 ppm/C), low loss (0.003-0.005) and high capacitance density film (200 nF/cm 2 ) directly on plastic substrates at temperatures less than 100 C. The films show BDVs greater than 10 volts and adequate leakage current behavior that is suitable for biased RF circuits.