Carbon nucleation on Si(100) using a negative carbon ion beam

Abstract

The initial nucleation stages of carbon film on Si(100) substrates were investigated by low energy electron diffraction (LEED) and Auger electron spectroscopy. In the initial stages, energetic carbon ions lead to a phase transformation from a two domain p(2×1) to a (1×1) LEED structure pattern after about 6×1015 carbon ion/cm2 dose (3 atomic layers). At room temperature, the energetic carbon ions are deposited as silicon carbide (SiC) up to a thickness of about 10 atomic layers. As the deposition temperature increases to 300 °C, the thickness of the SiC interlayer increases to 30 atomic layers. An increased carbon ion dose leads to the formation of sp3 or sp2 rich carbon film depending on the carbon ion energy and the deposition temperature. Higher energy (150 eV) C− ion beams and lower deposition temperatures (room temperature) produce sp3 rich carbon films. At 150 eV ion energy, the transition temperature from sp3 to sp2 rich carbon film during deposition is about 150 °C. Lower energy (<50 eV) C− ion beams at room temperature produce sp2 rich carbon films. During postdeposition annealing, the sp3 rich carbon film deposited at room temperature was converted to an sp2 rich carbon film above 740 °C.