Growth of InAs quantum dots on silicon substrates: Formation and characterization

Self-assembled InAs quantum dots (QDs) were grown by solid source molecular beam epitaxy on different Si substrate orientations (100) and (111) using Stranski-Krastanov growth mode. The grown QDs were characterized using atomic force microscopy.The evolution of size and shape of quantum dots with InAs coverage was examined after ex-situ surface preparation (oxide desorption) of the Si wafers with (NH4)HF etchant and in-situ with temperature between 730 C-750 C (pyrometer). Dashed-like InAs dots of high density were observed on (111) orientation compared to circular shaped QDs with a lower density on (100)Si orientation. The dot size and density grew with increasing InAs coverage and growth temperature up to 425 C. A narrow dots size distribution was observed for 1.7 ML InAs coverage at a growth temperature of 400 C.