Nanostructuring of Fe films by oblique incidence deposition on a FeSi 2 template onto Si(1 1 1): Growth, morphology, structure and faceting

Abstract

The growth of thin Fe films deposited at oblique incidence on an iron silicide template onto Si(1 1 1) single crystal has been investigated as a function of Fe thickness (0 < t Fe ⩽ 180 monolayers (MLs)) and incidence angle (0 ⩽ θ ⩽ 80°). The growth mode is determined in situ by means of scanning tunnelling microscopy (STM) and low energy electron diffraction (LEED). Stripes oriented perpendicularly to the incident atomic flux are formed for θ ⩾ 30°. Self-correlation functions are used to extract characteristic lengths from STM images. The correlation lengths in the direction of the incident flux ( ξ x ) and perpendicular to the atomic flux ( ξ y ) grow with different powers versus time ( ξ x ∝ t σ and ξ y ∝ t ρ , with σ = 0.34 ± 0.03 and ρ = 0.67 ± 0.03) following the exact solution of the (1 + 1) dimensional Kardar–Parisi–Zhang (KPZ) equation. The root mean square roughness follows also a scaling law for t Fe < 120 ML leading to a growth exponent β = 0.73 ± 0.02. Shadowing and steering effects are discussed on the basis of our STM data.