Abstract:
Ferroelectric materials have attracted an immense interest due to their vital
role in electronic industry with their wide variety of applications as ferroelectric
devices. Many ferroelectric materials, such as, barium titanate (BaTiO3), barium
strontium titanate (BST), potassium-di hydrogen phosphate (KDP), potassium nitrate
(KNO3), Lithium niobate (LiNb03), lead zirconate titanate (PZT), strontium bismuth
tantalate (SBT), strontium barium niobate (SBN) and tri-glycine sulphate (TGS) etc,
have been studied in a variety of forms like, single crystal, pellet and thin film for the
use of these materials in memory devices operated at low voltage. Usually the
ferroelectric materials has very high coercive field (—few kV/cm). Therefore it is
necessary to fabricate these materials in thin film form. These ferroelectric materials
are usually brittle and show difficulties for fabrication in thin film form.
In the recent past, thin films of many ferroelectric materials have been
fabricated by various methods viz., sputtering, pulse laser deposition (PLD), pulse
laser ablation (PLA), metal organic chemical vapor deposition (MOCVD), chemical
solution deposition (CSD), metal organic decomposition (MOD), molecular beam
epitaxy (MBE) and sol-gel. Another advantage of obtaining ferroelectrics in thin film
form is the possibilities of its integrate to the CMOS. This has been exploited to
fabricate dynamic random access memories (DRAMs), nonvolatile random access
memories (NV-RAMs) and ferroelectric random access memories (FRAMs). Thin
film transistors such as metal ferroelectric semiconductor field effect transistor
(MFSFET) has also been fabricated and studied. There are many other applications of
thin film ferroelectric materials as voltage tunable dielectric capacitor in resonators
and filters. Also recently thin film ferroelectrics arc finding increasing use in micro
electronic mechanical systems (MEMS) in producing highly sensitive actuators and sensors with low noise.
