Silicon carbide and oxide deposition using low energy (5-100 eV) beams of C⁺, O⁺, and CO⁺ ions

We have employed low energy (5-100 eV) beams of C⁺, O⁺, and CO⁺ ions to deposit carbide and oxide layers on a Si(1 1 1) surface under ultrahigh vacuum (UHV) conditions at room temperature. The deposited layers are characterized in situ by Auger electron spectroscopy (AES) and ultraviolet photoelectron spectroscopy (UPS). The effects of sputtering and thermal treatment on these layers are also examined. Atomic C⁺ and O⁺ ion beams efficiently produce carbide and oxide layers, respectively. Molecular CO⁺ ions collisionally dissociate on the surface to form a mixed carbide and oxide phase, the dissociation yield for CO⁺ increasing with beam energy in the range of 5-20 eV. The electronic energy gained during ion neutralization plays an extra role for CO⁺ dissociation. Upon thermal annealing, the O⁺-deposited layer changes into a more uniform phase. The CO⁺-deposited layer exhibits higher thermal stability when produced from a higher energy beam, which can be attributed to deeper penetration of carbon and oxygen and their different depth distributions.