Physical and electrical properties of yttrium oxide gate dielectrics on Si substrate with NH₃ plasma treatment

We report on the physical properties and electrical characteristics of Y2 O3 gate oxides grown on silicon substrates with N H3 plasma treatment by reactive radio-frequency sputtering. The interfacial chemistry of the high-k gate dielectric Y2 O3 has been investigated on nitrided and un-nitrided Si using X-ray photoelectron spectroscopy. We found that the Y2 O3 gate film having N H3 -based interface layer is very effective in reducing equivalent oxide thickness and leakage current as well as improving film qualities. This N H3 -nitrided layer is suggested to minimize interfacial Y Six Oy formation by limiting the amount of Si available to interact with the Y2 O3 layer. These Y2 O3 gate dielectrics exhibit excellent frequency dependence and weak temperature dependence of leakage current. They also show negligible charge trapping at high electric field stress.