Pulsed laser deposition of electronic ceramics

Abstract

High quality thin films of electronic ceramics are currently being deposited by pulsed laser deposition (PLD) for a variety of applications. Examples of these applications include ferroelectric thin films for active microwave electronics and rare-earth doped manganite thin films for uncooled infrared focal plane arrays (IRFPAs). Single phase and oriented Sr x Ba (1− x TiO 3 films have been deposited by PLD onto (100) substrates of LaAlO 3 for active microwave devices. The dielectric properties of these films has been measured using gold interdigital capacitors deposited on top of the film. A 2 : 1 change in the capacitance can be achieved using a 40 V bias across a 5–10 μm capacitor gap. The dissipation factor (measured at 1 MHz) depends on film composition and temperature. Rare-earth manganite (RE x M 1− x MnO δ) thin films have also been deposited by PLD for use in uncooled IRFPAs. The temperature dependence of the resistivity has been measured for La 0.67Ca 0.33MnO 3 and La 0.67Sr 0.33MnO 3 thin films deposited onto LaAlO 3 substrates. Film properties depend strongly on composition and post-deposition processing conditions to vary the oxygen stoichiometry. The temperature coefficient of resistance (TCR) has been measured to be between 2 and 15%. Based on preliminary measurements, these films will increase the sensitivity of the uncooled IR detector to be comparable or greater than a cooled detector based on HgCdTe.