Scaling during shadowing growth of isolated nanocolumns

Abstract

We observed a scaling behavior during the shadowing growth of isolated Si, Co, Cu, and W nanocolumnar structures on Si substrates using the oblique angle deposition with substrate rotation (also known as glancing angle deposition or simply GLAD). The width of the isolated columns, $W,$ grew as a function of column length, $d,$ in a power law form, $W\ensuremath{\sim}{d}^{p},$ where $p$ is the growth exponent and was measured to be $\ensuremath{\sim}0.28--0.34.$ It is argued that shadowing without diffusion should lead to $p=0.50$ and would cross over to 0.31 if one considers surface diffusion. It is of great interest to determine the mechanisms that would affect the value of $p$ since it is an important factor that would control the shape, final size, and spacing of the isolated nanocolumns eventually produced.