Recently, the ferroelectric materials are possible to study many fields for the application of the ferroelectric materials. The application of ferroelectric materials in random access memory devices tends to replace both magnetic core and magnetic bubble memories. And observed high electric field tunability with low losses makes this material suitable candidate for various voltage tunable microwave devices. Ferroelectric materials usually have high dielectric constants. From several published works, it was found that the sodium-potassium niobate, Na0.5K0.5NbO3(NKN) thin films grown on oxide substrate have a great dielectric and piezoelectric characteristics. Ferroelectric NKN thin films attract attention for their superior dielectric, piezoelectric, and crystalline properties. Therefore, we can use NKN thin films for many applications including non-volatile memory, sensors, optical switches, and ultrasonic transducers. The preferential development of anisotropic etching process for NKN thin films is desirable for highly intergrated ferroelectric application. Unfortunately, a small number of papers on NKN etch behavior published. The etch characteristics are not known appropriate accurately. This fact makes some difficulties for integration of NKN in the microelectronic technology.

In this work, we investigated etch characteristics of the NKN thin films in inductively coupled plasma. Both NKN etch rate and NKN/SiO2 etch selectivity were measured as functions of gas mixing ratio, input RF power, and dc bias voltage. The chemical reaction between plasma and NKN thin film surface were investigated by x-ray photoelectron spectroscopy (XPS). Field emission Auger electron spectroscopy (FE-AES) was used for the elemental analysis of the etched surfaces. Field emission scanning electron microscopy (FE-SEM) was used to investigate the etching profile.