Phosphorus-mediated growth of Ge quantum dots on Si(0 0 1)

• Published in: Journal of crystal growth 2005-05, Vol.278 (1), p.136-141
• Main Authors: Qin, J., Xue, F., Wang, Y., Bai, L.H., Cui, J., Yang, X.J., Fan, Y.L., Jiang, Z.M.
• Format: Article
• Language: English
• Subjects: A1. Low dimensional structures; A3. Molecular beam epitaxy; A3. Quantum dots; B2. Silicon germanium semiconductor; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of nanofabrication; Nanoscale materials and structures: fabrication and characterization; Physics; Quantum dots; Self-assembly
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2004.12.106

The influence of pre-deposited phosphorus atoms on the formation of self-assembled Ge quantum dots (QDs) on Si(0 0 1) is investigated by solid-source molecular beam epitaxy (MBE) and atomic force microscopy (AFM). AFM images show that P atoms have a great influence on the size and density of Ge QDs. In the presence of 0.1 ML P atoms, highly uniform self-assembled Ge QDs with a mean base size of 32 nm and an areal density of 1.4×10 11 cm −2 are obtained. These QDs are dome shaped with a size distribution width at half-maximum of 8 nm, which have a higher aspect ratio and are more uniform in size than dots obtained with the presence of C atoms. The strain effect on the nucleation and growth of Ge dots induced by P atoms is discussed. In situ annealing reveals the non-metastable nature of the as-grown uniform dots and they are formed under highly kinetically limited condition.