Electrical and Chemical Characteristics of Ta2O5 Gate Dielectrics on Ge-rich SiGe Heterolayers

Abstract

The charge trapping/detrapping behavior in ultra-thin tantalum pentoxide oxide (Ta2O5, equivalent oxide thickness ~1.76 nm) is presented under constant current stressing (CCS, 0.255 to 1.02 C. cm−2). The Ta2O5 film have been deposited on Ge-rich SiGe (Ge~85%) heterolayers using tantalum pentaethoxide [Ta(OC2H5)5] as an organometallic source at low temperature (~150 °C) by plasma enhanced chemical vapor deposition (PECVD) technique. The surface chemical states of Ta2O5 film has been analyzed by X-ray photo electron spectroscopy (XPS). Fixed oxide charge density (Qf/q) have been studied in constant current stressing.