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 um 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 um x 215 um 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 language | American English |
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Pages (from-to) | 1195-1204 |
Number of pages | 10 |
Journal | Crystal Growth and Design |
Volume | 23 |
Issue number | 2 |
DOIs | |
State | Published - 2023 |
NREL Publication Number
- NREL/JA-5900-84892
Keywords
- GaAs
- HVPE
- hydride vapor phase epitaxy
- photovoltaic
- planarizing overgrowth
- PV
- spalled surface