Strain-Compensated InGaAsP Superlattices for Defect Reduction of InP Grown on Exact-Oriented (001) Patterned Si Substrates by Metal Organic Chemical Vapor Deposition.

Ludovico Megalini,John Bowers,William Charles,Brandon Isaac,Aidan Taylor,Jonathan Klamkin,Simone Šuran Brunelli

doi:10.3390/ma11030337

Ludovico Megalini, John Bowers + Show 5 more

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https://doi.org/10.3390/ma11030337

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Abstract

We report on the use of InGaAsP strain-compensated superlattices (SC-SLs) as a technique to reduce the defect density of Indium Phosphide (InP) grown on silicon (InP-on-Si) by Metal Organic Chemical Vapor Deposition (MOCVD). Initially, a 2 μm thick gallium arsenide (GaAs) layer was grown with very high uniformity on exact oriented (001) 300 mm Si wafers; which had been patterned in 90 nm V-grooved trenches separated by silicon dioxide (SiO2) stripes and oriented along the [110] direction. Undercut at the Si/SiO2 interface was used to reduce the propagation of defects into the III–V layers. Following wafer dicing; 2.6 μm of indium phosphide (InP) was grown on such GaAs-on-Si templates. InGaAsP SC-SLs and thermal annealing were used to achieve a high-quality and smooth InP pseudo-substrate with a reduced defect density. Both the GaAs-on-Si and the subsequently grown InP layers were characterized using a variety of techniques including X-ray diffraction (XRD); atomic force microscopy (AFM); transmission electron microscopy (TEM); and electron channeling contrast imaging (ECCI); which indicate high-quality of the epitaxial films. The threading dislocation density and RMS surface roughness of the final InP layer were 5 × 108/cm2 and 1.2 nm; respectively and 7.8 × 107/cm2 and 10.8 nm for the GaAs-on-Si layer.

Highlights

The direct growth of Indium Phosphide (InP) and gallium arsenide (GaAs) on Silicon (Si) is of strong interest for the fabrication of monolithically integrated lasers in silicon photonics (SiPh) and, more generally, to realize opto-electronic integrated circuits (OEICs)
The direct heteroepitaxy of InP/GaAs on Si is extremely challenging: the large lattice mismatches between InP, GaAs, and Si (ε InP/Si ≈ 8%, εGaAs/Si ≈ 4%), their different polarities and thermal expansion coefficient cause the formation in high density of defects, including anti-phase domains (APDs), stacking faults, twins, threading, and misfit dislocations, which typically exceed
InP-on-Si has been rather limited successfully employed in GaAs-on-Si growth [18,19,20,21,22], GaN-on-sapphire [23,24], and GaN-on-Si [25,26], thisuse work, we propose the use superlattices as an additional whileIntheir in InP-on-Si has been rather limitedstrain-compensated tool to thewe defect density in InP-on-Si

Summary

Introduction

The direct growth of InP and GaAs on Silicon (Si) is of strong interest for the fabrication of monolithically integrated lasers in silicon photonics (SiPh) and, more generally, to realize opto-electronic integrated circuits (OEICs). Materials 2018, 11, x FOR PEER REVIEW thermal expansion coefficient cause the formation in high density of defects, including anti-phase domains (APDs), stacking faults, twins, threading, and misfit dislocations, which typically exceed 1. The material quaternary compounds is interesting because it allows us to independently control the system does not suffer of the typical growth issues of III-nitride compounds so that all not the strain and the composition of each strained layer. The InGaAsP material system does compressive and tensile layers can grown at their optimum temperature withoutand the tensile need oflayers long suffer of the typical growth issues of be so that all the compressive waiting time for temperature ramp up and cool down, as is the case in the. InGaN/AlGaN system can be grown at their optimum temperature without the need of long waiting time for temperature [28]. up and cool down, as is the case in the InGaN/AlGaN system [28]

Materials Growth μm thick GaAs layer was

InP-on-GaAs-on-Si

InGaAsP Strain Compensated Superlattice

InGaAsP

Conclusions