Abstract
We present a study of the effect of hydride vapor phase epitaxy (HVPE) growth conditions on the morphology of GaAs grown on vicinal and nominally exact (110) GaAs substrates. We evaluate epilayer surfaces using a combination of Nomarski microscopy and atomic force microscopy. The surface morphology strongly depends on the growth conditions employed, as well as the substrate orientation. On substrates offcut 3° toward (111)A, faceting generally develops under conditions in which the growth is Ga-limited, although Ga-limited growth is not the only requirement for faceting. Low growth temperatures lead to a faceted morphology, while higher growth temperatures favor smooth growth and facet-free morphology. We show that the surface morphology is kinetically controlled and that the tendency to facet correlates with the growth rate. 3D growth occurs on nominally exact substrates, resulting in hillock formation, but reduction of the group V precursor partial pressure results in smooth morphology. Overall, our results are consistent with models for step-bunching-induced surface faceting that invoke a negative Ehrlich-Schwoebel step-edge barrier.
Original language | American English |
---|---|
Pages (from-to) | 3916-3921 |
Number of pages | 6 |
Journal | Crystal Growth and Design |
Volume | 21 |
Issue number | 7 |
DOIs | |
State | Published - 7 Jul 2021 |
Bibliographical note
Publisher Copyright:©
NREL Publication Number
- NREL/JA-5900-78864
Keywords
- (110) oriented GaAs
- atomic force microscopy
- GaAs
- HDPE
- III-V
- Nomarsky contrast microscopy
- photovoltaic
- PV
- surface morphology