Silicon nitride thin films deposited using electron-beam evaporation in an RF plasma MBE system

Abstract

Silicon nitride (SiNx) thin films were deposited on (100) Si wafers in a molecular-beam epitaxy growth chamber equipped with a customized multipocket electron-beam evaporator, a Si effusion cell, and an RF plasma source for reactive nitrogen. The films were characterized using atomic-force microscopy, spectroscopic ellipsometry, and specular x-ray reflectivity. For films deposited using an electron-beam Si source with N/Si > 1.33, the deposition temperature determined the density and refractive index. Stoichiometric Si3N4 films were produced when the deposition temperature was greater than 725 °C, in agreement with our previous results that used an effusion cell for Si. By using the electron-beam Si source, an order of magnitude increase in SiNx deposition rate was achieved over the conventional effusion cell method.