Section 1: Interfacial reactions and grain growth in ferroelectric SrBi{sub 2}Ta{sub 2}O (SBT) thin films on Si substrates
- Virginia Polytechnic Institute and State Univ., Blacksburg, VA (United States); and others
Much of the cost of traditional infrared cameras based on narrow-bandgap photoelectric semiconductors comes from the cryogenic cooling systems required to achieve high detectivity. Detectivity is inversely proportional to noise. Generation-recombination noise in photoelectric detectors increases roughly exponentially with temperature, but thermal noise in photoelectric detectors increases only linearly with temperature. Therefore `thermal detectors perform far better at room temperature than 8-14 {mu}m photon detectors.` Although potentially more affordable, uncooled pyroelectric cameras are less sensitive than cryogenic photoelectric cameras. One way to improve the sensitivity to cost ratio is to deposit ferroelectric pixels with good electrical properties directly on mass-produced, image-processing chips. `Good` properties include a strong temperature dependence of the remanent polarization, P{sub r}, or the relative dielectric constant, {epsilon}{sub r}, for sensitive operation in pyroelectric or dielectric mode, respectively, below or above the Curie temperature, which is 320 C for SBT. When incident infrared radiation is chopped, small oscillations in pixel temperature produce pyroelectric or dielectric alternating currents. The sensitivity of ferroelectric thermal detectors depends strongly on pixel microstructure, since P{sub r} and {epsilon}{sub r} increase with grain size during annealing. To manufacture SBT pixels on Si chips, acceptable SBT grain growth must be achieved at the lowest possible oxygen annealing temperature, to avoid damaging the Si chip below. Therefore current technical progress describes how grain size, reaction layer thickness, and electrical properties develop during the annealing of SBT pixels deposited on Si.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- OSTI ID:
- 494124
- Report Number(s):
- ORNL/TM-13399; ON: DE97005392; TRN: 97:003310-0020
- Resource Relation:
- Other Information: PBD: Apr 1997; Related Information: Is Part Of Advanced Industrial Materials (AIM) program. Annual progress report. FY 1996; PB: 292 p.
- Country of Publication:
- United States
- Language:
- English
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