Planarizing Spalled GaAs(100) Surfaces by MOVPE Growth

Journal Article · Wed Nov 13 00:00:00 EST 2024 · Crystal Growth and Design

DOI:https://doi.org/10.1021/acs.cgd.4c01152· OSTI ID:2525873

Forcade, Gavin P. ^[1]; McMahon, William E. ^[2]; Yoo, Nicholas ^[3]; Neumann, Anica N. ^[4]; Young, Michelle ^[2]; Goldsmith, John ^[2]; Collins, Sarah ^[2]; Hinzer, Karin ^[1]; Packard, Corinne E. ^[4]; Steiner, Myles A. ^[2]

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1. Univ. of Ottawa, ON (Canada)
2. National Renewable Energy Laboratory (NREL), Golden, CO (United States)
3. Colorado School of Mines, Golden, CO (United States)
4. National Renewable Energy Laboratory (NREL), Golden, CO (United States); Colorado School of Mines, Golden, CO (United States)

III-V photovoltaic devices have demonstrated exceptional performance across various applications, with controlled crystal fracturing, known as controlled spalling, emerging as a promising method to reduce costs by enabling substrate reuse. Spalling GaAs(100) substrates, a commonly used substrate in III-V photovoltaics, results in faceted ridges that must be planarized to grow high-quality photovoltaic devices. Here, in this study, we demonstrate that a GaAs(100) wafer offcut toward [$$0\bar{11}$$] and spalled toward [$011$] can be efficiently planarized by growing C:GaAs by metal-organic vapor phase epitaxy (MOVPE) on the surface, with up to 95% of the nominally deposited material used to fill the valleys between ridges. We find that reducing the offcut to 2° enhances the planarizing capability of C:GaAs. A surface morphology model indicates that the density of surface dangling bonds significantly influences the growth evolution of undoped GaAs surfaces. In contrast, the model suggests that the effectiveness of C:GaAs as a smoothing layer stems from modifying the atomic surface structure and, consequently, the associated sticking coefficients of the facets, which can alter the evolution of surface morphology. Our findings provide guidelines for the epitaxial planarization of semiconductor surfaces and improve the understanding of MOVPE growth on nonplanar surfaces.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States)
• Sponsoring Organization: Natural Sciences and Engineering Research Council of Canada (NSERC); New Frontiers in Research Fund (NFRF); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
• Grant/Contract Number: AC36-08GO28308
• OSTI ID: 2525873
• Report Number(s): NREL/JA--5900-90856
• Journal Information: Crystal Growth and Design, Journal Name: Crystal Growth and Design Journal Issue: 23 Vol. 24; ISSN 1528-7505; ISSN 1528-7483
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
GaAs
III-V
MOCVD
MOVPE
PV
SOLAR ENERGY
carbon tetrachloride
patterned substrate
photovoltaic
spalling
substrate reuse
surface planarization