Pulsed laser deposition of ferroelectric thin films for active microwave electronic devices

摘要

Abstract: High quality thin films of Sr$-x$/Ba$-(1-x)$/TiO$-3$/ are currently being grown using pulsed laser deposition (PLD). These films are being used for the construction of frequency tunable microwave electronic devices. In particular, a low phase noise, voltage controlled oscillator (1.5 - 2.5 GHz) is currently being developed. Single phase and oriented Sr$- x$/Ba$-(1-x)$/TiO$-3$/ films have been deposited by PLD onto (100) LaAlO$-3$/ and MgO and single crystal Ag films. The dielectric properties of these films has been measured at 1 MHz and between 1 and 20 GHz. A 75% change in the capacitance can be achieved using a 40 V bias across a 5 micrometer interdigital capacitor gap (80 kV/cm). The dissipation factor (measured at 1 MHz) depends on film composition and temperature. Dielectric loss measurement at 1 - 20 GHz have shown a dielectric loss tangent as small as 1.25 multiplied by 10$+$MIN@2$/. !8