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

Abstract

The 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 due to them being rate-limited by aggregation, which reduces the surface energy at substrate temperatures above ∼580 °C. Moreover, at temperatures below ∼580 °C, semi-ellipsoidal shaped Si-QDs are formed because the precursor supply is a dominant factor.