Coalescence of GaP on V-Groove Si Substrates

Abstract

Here, we study the morphology and dislocation dynamics of metalorganic vapor phase epitaxy (MOVPE)-grown GaP on a V-groove Si substrate. We show that Si from the substrate stabilizes the (0 0 1) GaP facet, which is critical for achieving coalescence. The SiN x caps covering the (0 0 1) tops of the V-grooves must be sufficiently small for the 3 × 1 GaP surface reconstruction caused by Si to continue to influence the GaP coalescence while the V-grooved sidewalls are covered. If the SiN x caps are too large, (1 1 1) diamond faceting develops in the GaP, and coalescence does not occur. On samples where coalescence is successful, we measure a root-mean-square roughness of 0.2 nm and a threading dislocation density of 5 × 10 7 cm −2 . Dislocation glide was found to begin during coalescence through transmission electron microscopy. With further TDD reduction, these GaP on V-groove templates will be suitable for III-V optoelectronic device growth.

In Situ Smoothing of Facets on Spalled GaAs(100) Substrates during OMVPE Growth of III–V Epilayers, Solar Cells, and Other Devices: The Impact of Surface Impurities/Dopants

“…In both cases, the growth conditions and spall direction can affect the resulting morphological evolution, by changing both the sticking coefficient and surface mobility of adatoms on the surface. (The morphological evolution of epilayers grown on patterned substrates is analogous to the work presented here and can provide some useful insights. − ).…”

“…During GaP growth on offcut Si(100), there is evidence that Si from the substrate can create stabilized (100) facets, thereby altering the surface morphology . Both explicit and background Si doping of GaP surfaces has also been used to flatten GaP surfaces during GaP growth on v-grooved Si(100) …”

“… 15 Both explicit and background Si doping of GaP surfaces has also been used to flatten GaP surfaces during GaP growth on v-grooved Si(100). 26 …”

“…15 Both explicit and background Si doping of GaP surfaces has also been used to flatten GaP surfaces during GaP growth on v-grooved Si(100). 26 Finally, different results can be expected for MBE, OMVPE, and HVPE, because each growth method can supply additional elements to the surface through various pathways. The reconstruction of Ga x In 1−x P(100) is qualitatively different in OMVPE than in MBE, because OMVPE-prepared surfaces incorporate atomic hydrogen provided by precursors like PH 3 39,40 and AsH 3 .…”

III-V PV Cell Core Capability (Final Technical Report)

“…Additionally, as shown the RMS roughness of the improved coalesced GaP on v-groove Si was measured to be 0.2 nm, comparable to a CMP Si wafer (Fig. 31b) [49]. To reduce the threading dislocation density, we used the structures as reported in [50] that grew a GaAs buffer layer on top of the GaP/Si templates.…”