Formation of high quality silicon nitride films using microwave excitation plasma

The electric characteristics Si₃N₄ films the interface characteristics of Si₃N₄/Si formed by newly developed microwave-excited highdensity plasma are described. The leakage current through the Si₃N₄ films reduces 3 orders of magnitude and the lifetime improves 30,000 times compared to the conventional SiO₂ films formed by a thermal oxidation. The MISFET on Si(100) surface with gate insulator of Si₃N₄ films have more excellent performance compared to that with conventional SiO₂ films. The crystal orientation of silicon wafer surface is affected to the subnitride at Si₃N₄/Si interface. The subnitride at Si ₃N₄/Si decreases with an increase in Si atom density in the silicon wafer surface, as a result, the quantity of subnitride is lowest in Si(110) surface than any other surfaces. The valence band offset at Si ₃N₄/Si interface is independent of a silicon wafer surface. Si₃N₄ films formed by the microwave excited plasma is essential to high performance and low leakage LSI devices.