Abstract
System integration and miniaturization demands are driving integrated thin film capacitor
technologies towards ultrahigh capacitance densities for noise-free power supply, power
conversion and efficient power management. Hydrothermal route can deposit crystalline
ferroelectric films at low temperatures of less than 150 C. It is hence an attractive route for
integrating high permittivity thin film capacitors on organic, silicon or flex substrates.
However, hydrothermal films are not commercialized so far because of their inferior
insulation characteristics. Embedded hydroxyl groups are attributed to be the cause for
high leakage currents, temperature dependent properties and lower Breakdown Voltages
(BDVs). This paper discusses the dielectric characteristics such as capacitance density,
leakage currents and Temperature Coefficient of Capacitance (TCC) of hydrothermal
barium titanate films and correlates them to the embedded water and OH groups, film
morphology, stoichiometry and crystallinity. With thermal treatment, majority of the OH
groups can be removed leading to improved insulation characteristics. The room
temperature I-V characteristics agreed with ionic conduction models for films baked at 160
C while higher baking temperatures of above 300 C resulted in Poole-Frenkel type
conduction. A brief perspective is provided on the suitability of hydrothermal thin film
capacitors for power supply applications.
