HOMOEPITAXY AND CONTROLLED OXIDATION OF SILICON AT LOW-TEMPERATURES USING LOW-ENERGY ION-BEAMS

Homoepitaxy and controlled oxidation of silicon at low temperatures ha ve been achieved using a dual source, mass-selected, low-energy, ion b eam deposition system. For Si homoepitaxy, Si-28(+) ions in the energy range 8-40 eV were used to grow films on Si{100} in the temperature r ange of 50-750 degrees C. The films were analyzed in situ by reflectio n high-energy electron diffraction and Auger electron spectroscopy (AE S) and ex situ by high-resolution transmission electron microscopy, Ru therford backscattering spectrometry, and atomic force microscopy. For silicon oxidation, films of SiO2 on Si{100} at room temperature were grown by using 25 eV beams of Si-28(+) and O-16(+). Fast switching of the magnetic sectors allows deposition of these ions in alternating pu lses. The pulse increments used were 1x10(14) cm(-2) for Si+ and 4X10( 14) cm(-2) for O+. Analysis of the oxide films by in situ AES and ex s itu x-ray photoelectron spectroscopy show that the films are SiO2, tha t the suboxides are localized at the interface, and that there is no l imitation to the thickness of the oxide films that can be grown. The e ffects of ion energy and substrate temperature, contamination, and sur face damage on the growth mechanism are discussed. (C) 1995 American V acuum Society.