Texture Development in Modified Lead Titanate Thin Films Obtained by Chemical Solution Deposition on Silicon‐Based Substrates

An advanced method of X‐ray diffractometry analysis, the quantitative texture analysis, is used in this work to study the preferential orientations of ferroelectric lanthanum‐modified lead titanate thin films, to establish the factors affecting their development. The new, more reliable, texture data obtained allows us to discuss previous models of texture development in chemical‐solution‐deposited films. The results show that a fiber type, mixed <100>,<001> preferential orientation, is obtained when high heating rates are used during crystallization. The degree of texture of these films decreases when successive layers are deposited before a simultaneous crystallization of the ensemble is conducted. This undesirable effect is avoided through layer‐by‐layer crystallization, because of the preferential nucleation of <100>,<001> crystals at the interface between layers. The use of a titanium layer on the platinized silicon‐based substrate leads to the development of an additional fiber <111> texture component. In this case, the layer‐by‐layer crystallization process cannot avoid the loss of the degree of orientation (texture index) with the increase of film thickness. This is mainly caused by the appearance of interlayer porosity, which disrupts the growth of <111>‐oriented grains into upper layers.