Enhanced sintering and functional properties of PZT thick films processed using local infrared irradiation

Significantly enhanced functional properties have been observed in lead zirconate titanate thick films when sintered for 1 min using focussed infrared irritation from a halogen bulb. By scanning the heat affected zone similar enhancements in properties were obtained when scan speeds of between 0.06 and 0.16 mm/s were used. Scanning at slower speeds resulted in incomplete sintering while sintering at higher speeds resulted in a degradation of properties. Where enhancements in properties were observed relative permittivity was increased from between 200 and 300 to 600 and 700. Piezoelectric properties (d ₃₃) were observed to increase from 20–30 pC/N to between 60 and 80 pC/N. The enhancement in properties were attributed to the improved densification and grain growth brought about by the high ramp rates and short sintering times achievable using focussed IR irradiation and the ability of the surrounding film to accommodate the sintering strains. Combining multiple scan lines in a rastering pattern failed to yield similar improvements in properties due to effects of stopping and restarting the sintering process in the scan overlap regions and the inability of the film to accommodate the sintering strains across large areas.