METHOD FOR PRODUCING SELF-POLARIZED FERRO-ELECTRIC LAYERS, ESPECIALLY PZT LAYERS, WITH A RHOMBOHEDRAL CRYSTAL STRUCTURE

摘要

A method for producing self-polarized ferroelectric layers, in particular PZT layers, with a rhombohedral crystal structure includes providing a substrate and heating it to a temperature T1. Afterward the layer with a rhombohedral crystal structure is applied to the substrate by means of a sputtering method. This layer includes a Zr-deficient layer with a Curie temperature TC1 and a Zr-abundant layer with a Curie temperature TC2 wherein TC2TC1T1. After the ending of the application process, the heating of the substrate is also discontinued so that the substrate cools. As a result of the cooling the Zr-deficient layer and then the Zr-abundant layer reach their Curie temperature, and change into the ferroelectric phase and become self-polarized in the process. The polarization already present in the Zr-deficient layer induces the polarization in the Zr-abundant layer, with the result that both layers are self-polarized after the cooling process.