Study of wet chemical etching of BaSrTiO3 ferroelectric thin films for intelligent antenna application

Wet chemical etching of (Ba1-xSrx)TiO3 thin films has been investigated. The etchant was prepared from buffered hydrofluoric acid (BHF) and nitric acid (HNO3), BHF being the reactive agent while HNO3 acts as a catalyst. X-ray diffraction and energy dispersive X-ray spectrometry were performed in order to qualitatively and quantitatively follow the etching process. Scanning electron microscopy and a profilometer were used for determining the etching quality. The ferroelectric thin films were elaborated by a modified sol-gel process and by spin-coating on insulating (Si-wafers) or metal (stainless steel) substrates. Classic photolithography technique and a positive photo resist were used for the transfer of the patterns. Appropriate water dilution reduces the etching speed, thus allowing a better visual control of the process.