Abrupt GaP/Si hetero-interface using bistepped Si buffer

Abstract

International audienceWe evidence the influence of the quality of the starting Si surface on the III-V/Si interface abruptness and on the formation of defects during the growth of III-V/Si heterogeneous crystal, using high resolution transmission electron microscopy and scanning transmission electron microscopy. GaP layers were grown by molecular beam epitaxy on vicinal Si (001). The strong effect of the Si substrate chemical preparation is first demonstrated by studying structural properties of both Si homoepitaxial layer and GaP/Si heterostructure. It is then shown that choosing adequate chemical preparation conditions and subsequent III-V regrowth conditions enables the quasi-suppression of micro-twins in the epilayer. Finally, the abruptness of GaP/Si interface is found to be very sensitive to the Si chemical preparation and is improved by the use of a bistepped Si buffer prior to III-V overgrowth

Observation of Twin-free GaAs Nanowire Growth Using Template-Assisted Selective Epitaxy

“…In early discussions on defect formation in planar epitaxial growth, and in more recent work, , it was shown that impurities located on the (hetero-) epitaxial interface can trigger bonding errors and SFs in {111} planes. The considered impurities can be extrinsic, e.g., carbon contamination, or intrinsic from a group III overdose, e.g., Ga cluster.…”

“…The considered impurities can be extrinsic, e.g., carbon contamination, or intrinsic from a group III overdose, e.g., Ga cluster. Therefore, rigorous surface cleaning and adjusted growth conditions were found to be critical to achieve defect-free epitaxy. , In ELO the crystal grows laterally over a SiO 2 stripe and thus follows a SiO 2 - III–V interface, which could also trigger SFs. For InP ELO on InP no SFs were observed in the overgrown layers, while in the heteroepitaxial case on a Si(001) substrate, rare occurrence of SFs was noticed and is suggested to stem from residual stress of the Si-InP heterojunction area.…”

Influence of PE‐ALD of GaP on the Silicon Wafers Quality

“…Gallium phosphide is one of the most perspective candidates for fabrication of multi‐junction solar cells on silicon wafers. Firstly, lattice mismatch between Si and GaP is only 0.4% so GaP can be grown on silicon for the fabrication of the bottom subcell based on GaP/Si heterojunction by different epitaxial methods (MBE and VPE) . Further, novel materials (In)GaP(NAs) with small nitrogen content (called dilute nitrides) can be lattice‐matched to GaP.…”