摘要
A CMOS compatible process is prese nted in order to grow self-catalyzed InAs nano wires on silic on by molecular beam epitaxy. The crucial step of this process is a new in-situ surface preparation under hydrogen (gas or plasma) during the substrate degassing combined with an in-situ arsenic ann eali ng prior to growth. Morphological and structural characterizati ons of the InAs nano wires are prese nted and growth mecha nisms are discussed in detail. The major in flue nee of surface termi nation is exposed both experime ntally and theoretically using statistics on ensemble of nanowires and density functional theory (DFT) calculations. The differences observed between Molecular Beam Epitaxy (MBE) and Metal Organic Vapor Phase Epitaxy (MOVPE) growth of I nAs nano wires can be explai ned by these differe nt surfaces termi nations. The transition between a vapor solid (VS) and a vapor liquid solid (VLS) growth mechanism is presented. Optimized growth conditions lead to very high aspect ratio nano wires (up to 50 nm in diameter and 3 micron in len gth) without passi ng the 410℃ thermal limit, which makes the whole process CMOS compatible. Overall, our results suggest a new method for surface preparation and a possible tuning of the growth mechanism using different surface termi nations.
