Effect of in-situ nitrogen doping into MOCVD-grown Al/sub 2/O/sub 3/ to improve electrical characteristics of MOSFETs with polysilicon gate

Abstract

The effect of nitrogen doping into Al/sub 2/O/sub 3/ gate dielectric grown by Metal Organic Chemical Vapor Deposition (MOCVD) on MOS device characteristics is described for the first time. The nitrogen doped Al/sub 2/O/sub 3/ (Al/sub 2/O/sub 3/:N) MOSFET has an interface trap density (D/sub it/) as low as 4.3/spl times/10/sup 10/ cm/sup -2/ eV/sup -1/, half that of non-doped Al/sub 2/O/sub 3/ (1.0/spl times/10/sup 11/ cm/sup -2/ eV/sup -1/), and has less C-V hysteresis (39 mV) than that (69 mV) of Al/sub 2/O/sub 3/. These improvements are attributed to nitrogen doping into Al/sub 2/O/sub 3/, which also improves the corresponding MOSFET characteristics of current drivability (I/sub dsat/).