Silicon nitride films grown on silicon below 300 °C in low power nitrogen plasma

Device quality silicon nitride films ranging in thickness down to 30 Å were successfully grown on silicon at temperatures below 300 °C in a radio frequency (rf) nitrogen plasma. The growth rate was controlled in the range 5-100 Å/h by changing nitrogen pressure, rf power, and growth temperature. Electron microscopy and Auger spectroscopy showed that the films were amorphous, microcrack-free, close to stoichiometry Si₃N₄, and formed a sharp interface with the Si substrate. The breakdown voltage of Al-Si₃N₄-Si capacitors was about (1.3±0.2)×10⁷ V/cm and the typical density of the leakage current was below 3×10^-7 A/cm² at 5 V bias for films 70 Å thick.