STUDY OF SPRAY DEPOSITED FERROELECTRIC FILMS ON POROUS SILICON

Abstract

Ferroelectric oxide materials with a perovskite structure have promising applications in electronic devices such as random access memories, sensors, actuators, infrared detectors, and so on. Recent advances in science and technology of ferroelectrics have resulted in the. feature sizes of ferroelectric-based electronic devices entering into nanoscale dimensions. Generally, ferroelectric ceramics in film form are suitable for the microelectronic applications. The striking photoluminescence properties of porous silicon have attracted considerable research interest since their discovery in 1990. Porous silicon is constituted by a nanocrystalline skeleton (quantum sponge) immersed in a network of pores. As a result, porous silicon is characterized by a very large internal surface area (of the order of 500m2/cm3). This internal surface is passivated but remains highly chemically reactive. This is one of the essential features of this new and complex material. The work in the report presents a new undiscovered area for research on porous silicon as a template for ferroelectric materials deposition. The combination of PS with one or more materials which are also nanostructured due to their deposition within the porous matrix is discussed. Emphasis has been put on macroporous . silicon, offering a, quasi-regular pore arrangement, employed as template for filling with ferroelectric materials. The correlation between morphology and ferroelectric behavior of such semiconducting/ferroelectric systems will be determined. By varying the average size of the pores we can tune - the ferroelectric properties. It has been found that the increase in average pore size increases the remanent polarization of deposited composite film first and saturates later on The optimum value of remanent polarization (Pr) is 41 μC/cm2. The switching kinetics of the composite films have been analyzed by different theoretical model. The switching current; data are fitted well to infinite-grain model (IGM) in the lower time region and deviate in later time region. The nucleation limited switching (NLS) model gives excellent agreement with the experimental polarization reversal transients throughout the whole time range.