Self-assembling mechanism of Si-QDs on thermally grown SiO₂

Abstract

Self-assembling formation of Si-quantum-dots (Si-QDs) on as-grown SiO2 layers was shown by controlling the early stages of low-pressure chemical vapor deposition of SiH4. The QD height and radius distributions assessed by atomic force microscopy and scanning electron microscopy images revealed that the Si-QDs become hemispherical caused by being rate-limited by aggregation that reduces surface energy at substrate temperatures above ~580°C. Moreover, at temperatures below ~580°C, semiellipsoidal-shaped Si-QDs are formed because the precursor supply is a dominant factor.