Effect of Underlayer in the Growth of Ta2o5 Films Prepared using MOCVD Method for Metal-Insulator-Metal Capacitors in RF-BiCMOS Technology

Abstract

AbstractThe properties of Ta2O5 thin films with respect to different underlayer stack have been investigated. At first, a set of samples were produced at various conditions as an underlayer of Ta2O5 film deposition. Then, Ta2O5 films were grown using a MOCVD method with Ta(OC2H5)5 pre-curser at 440 °C. The Process parameters for Ta2O5 films were remained same through the preparation of the sample set. The results were analyzed using various methods including thickness measurement, SEM, stress measurement, X-ray diffraction (XRD), and electrical property measurements. Different grain structures and growth rates were observed with respect to the different underlayer preparation condition mainly as a function of deposition temperature. The deposition rate varied from 0.6 Åsec to 1.8Åsec depend on different underlayer. Crystalline Ta2O5 films with large-grain-size were obtained on Aluminum/TiN underlayer stack. Films with crystalline structure show better leakage current characteristics than the amorphous one.