Growth Process of Silicon Over SiO2 by CVD: Epitaxial Lateral Overgrowth Technique

Abstract

The epitaxial lateral overgrowth (ELO) process of depositing single crystal silicon over a SiO2 mask is described. A CVD technique has been developed which consists of depositing silicon in openings in a SiO2 mask and then growing the silicon laterally over the SiO2 film. By optimizing the normalHCl concentration in the gas, growth temperature, and the use of a growth procedure based on a series of growth/etch steps the nucleation of polysilicon over SiO2 has been eliminated and monocrystalline ELO films have been grown. Low defect density ELO films have been achieved by orientating the oxide islands along the [010] direction on (100) substrates. The growth kinetics, overgrowth morphology, and defect formation in ELO films are described as a function of the growth conditions. One can conclude that optimization of the growth process has allowed us to grow monocrystalline, low defect density ELO films with smooth mirrorlike surfaces.

Understanding of crystal growth mechanisms through experimental studies of semiconductor epitaxy

“…This structure is the same as that of epitaxial lateral overgrowth (ELO), which has been employed to get silicon on insulator (SOI) structure [28]. We have extended this idea and renamed as microchannel epitaxy (MCE) as a technique to take lattice information through narrow channel but to eliminate defect information [29].…”

Twin-free InGaAs thin layer on Si by multi-step growth using micro-channel selective-area MOVPE

“…Heteroepitaxy using selective-area growth (SAG) [6][7][8][9][10][11][12][13] is a desirable approach to realize such integration because (1) it is a self-aligned process, therefore, the growth position can be decided in advance, (2) it is easy to obtain thin films by controlling a growth rate and/or a growth time, (3) dislocations and defects, generated by the difference in lattice constants and thermal expansion coefficients between a III-V layer and Si, can be avoided by restricting the growth area to a smaller one. In the case of heteroepitaxy of III-V semiconductors on Si, threedimensional nuclei tend to appear at the initial stage of the growth [14][15][16].…”

Effect of Ga content on crystal shape in micro-channel selective-area MOVPE of InGaAs on Si

“…Micro-channel selective area growth (MC-SAG) [3] is a promising technique for reducing dislocations in heteroepitaxial growth. Restriction of the growth area is essential for obtaining a single-grained epitaxial island, which then overgrows the mask margin by epitaxial lateral overgrowth (ELO) [4,5]. Threading dislocations tend to appear at the interface between III/V semiconductors and Si due to lattice mismatch, but they do not spread laterally to the material grown on the mask.…”