Device Processing Aspects of Ion Beam Nitridation

Abstract

Silicon nitride local oxidation masking layers fabricated by low energy nitrogen ion implantation into silicon have been employed in the fabrication of n‐channel silicon‐gate MOSFET's. Processing considerations which are unique to the application of these very thin (10 nm) silicon nitride films are detailed. The effects of oxygen contamination during implantation are described, as are those of subsequent wafer processing steps such as RCA cleaning and oxygen plasma photoresist stripping. It is also shown that resputtered material from the wafer holder can result in iron contamination of the resulting silicon nitride films. Finally, we show that careful attention to these possible problems can produce transistors with reasonable current‐voltage characteristics, as compared to conventionally processed devices.