Design of Planarizing Growth Conditions on Unpolished and Faceted (100)-Oriented GaAs Substrates Using Hydride Vapor Phase Epitaxy

Anna Braun, Kevin Schulte, John Simon, Aaron Ptak, Corinne Packard

Research output: Contribution to journalArticlepeer-review

5 Scopus Citations

Abstract

We performed a design of experiments (DoE) analysis to determine the effect of various growth parameters on in situ planarizing overgrowth of rough substrates using hydride vapor phase epitaxy (HVPE). We used two types of rough (100)-oriented GaAs substrates to compare the effect of the initial morphology on the epitaxial growth behavior: an irregular, as-cut surface resultant from cutting the wafer from a GaAs boule and a regularly faceted surface produced by controlled spalling. The DoE analysis identified trends in the overgrowth behavior with changing growth conditions, and we used these trends to design favorable planarization growth conditions for each surface type. These favorable conditions enabled full planarization of a spalled surface with >2.5 μm facet height within 10.8 min of growth. The root mean squared (RMS) surface roughness of the resulting (100) surface was 24.5 nm over a 286 μm × 215 μm area. Our results show that planarization growth by HVPE is a promising technique to enable device growth directly on rough substrates, and the trends revealed through DoE analysis indicate a path toward further optimization of planarization growth conditions for as-cut and spalled surfaces.

Original languageAmerican English
Pages (from-to)1195-1204
Number of pages10
JournalCrystal Growth and Design
Volume23
Issue number2
DOIs
StatePublished - 2023

Bibliographical note

Publisher Copyright:
© 2023 American Chemical Society.

NREL Publication Number

  • NREL/JA-5900-84892

Keywords

  • GaAs
  • HVPE
  • hydride vapor phase epitaxy
  • photovoltaic
  • planarizing overgrowth
  • PV
  • spalled surface

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