氧氣微波電漿表面處理對五氧化二鉭薄膜性質改進之研究

Abstract

In this work we studied the oxygen microwave plasma modification on structure and electrical properties of tantalum pentoxide (Ta2O5) films deposited by magnetron sputtering process. The x-ray and Auger electron spectroscopy analyses (AES) revealed that the [O]/[Ta] ratio of the films is much closer to exact stoichiometery after the application of plasma treatment. The surface roughness and the sizes of intergranular voids of plasma-treated Ta2O5 films were effectively reduced, as observed by scanning electron microscopy (SEM), atomic force micro-scopy (AFM) and cross- sectional transmission electron microscopy (XTEM). The plasma-induced structure densification was also beneficial to the electrical properties of Ta2O5 films whose breakdown voltages were improved up to 3.5 times, as indicated by current-voltage (I-V) measurement. However, plasma modification seemed to be effective to thicker Ta2O5 flims. For the Ta2O5 films of thickness less than 10nm, the plasma treatment would result too many implanted defects which deteriorate both structure and electrical properties of the films.