Leakage current comparison between ultra-thin Ta₂O₅ films and conventional gate dielectrics

Capacitors with ultra-thin (6.0-12.0 nm) CVD Ta/sub 2/O/sub 5/ film were fabricated on lightly doped Si substrates and their leakage current (I/sub g/-V/sub g/) and capacitance (C-V) characteristics were studied. For the first time, samples with stack equivalent oxide thickness around 2.0 nm were compared with ultra-thin silicon dioxide and silicon oxynitride. The Ta/sub 2/O/sub 5/ samples showed remarkably lower leakage current, which not only verified the advantages of ultra-thin Ta/sub 2/O/sub 5/ as dielectrics for high density DRAM's, but also suggested the possibility of its application as the gate dielectric material in MOSFET's.