Thermally induced morphology evolution of pit-patterned Si substrate and its effect on nucleation properties of Ge dots
Journal
Nanotechnology
Journal Volume
23
Journal Issue
1
Date Issued
2012
Author(s)
CHIEH-HSIUNG KUAN
Chen, H.-M.
Kuan, C.-H.
Suen, Y.-W.
Luo, G.-L.
Lai, Y.-P.
Wang, F.-M.
Chen, S.-T.
CHIEH-HSIUNG KUAN
Abstract
We demonstrate the effect of the pre-growth heat treatment process on the nucleation properties of Ge dots grown on pit-patterned Si(001) substrates. The prefabricated 200 nm diameter pits inherently evolve into truncated inverted pyramids (TIPs) with (110) base edges and a 7°-9° sidewall slope during heat treatment; this morphology transformation is robust against variations in shape and orientation of the pit patterns. Uniform Ge dots with an areal density of 4 × 10(9) cm(-2) were obtained on the Si substrates having TIPs. Each TIP contains four aligned Ge dots locating symmetrically with respect to (110). These dots exhibit an elliptical dome shape with major axis oriented along (100). The nucleation position, shape and spatial orientation of these Ge dots coincide with the calculated surface chemical potential distribution of the TIP.
SDGs
Type
journal article