The divacancies in SiC are a family of paramagnetic defects that show promise for quantum communication technologies due to their long-lived electron spin coherence and their optical addressability at near-telecom wavelengths. Nonetheless, a high-fidelity spin-photon interface, which is a crucial prerequisite for such technologies, has not yet been demonstrated. Here, we demonstrate that such an interface exists in isolated divacancies in epitaxial films of 3C-SiC and 4H-SiC. Our data show that divacancies in 4H-SiC have minimal undesirable spin mixing, and that the optical linewidths in our current sample are already similar to those of recent remote entanglement demonstrations in other systems. Moreover, we find that 3C-SiC divacancies have a millisecond Hahn-echo spin coherence time, which is among the longest measured in a naturally isotopic solid. The presence of defects with these properties in a commercial semiconductor that can be heteroepitaxially grown as a thin film on Si shows promise for future quantum networks based on SiC defects. DOI:https://doi.org/10.1103/PhysRevX.7.021046 Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Published by the American Physical Society

https://link.aps.org/pdf/10.1103/PhysRevX.7.021046

Isolated Spin Qubits in SiC with a High-Fidelity Infrared Spin-to-Photon Interface

https://iopscience.iop.org/article/10.1088/1361-6641/aad831/pdf

Review of SiC crystal growth technology

Recent advances in 4H-SiC epitaxy for high-voltage power devices

The crystallinity and wafer uniformity of ( 2 ¯ 01 ) and (010) oriented β-Ga2O3 substrates grown by edge-defined film-fed growth (EFG) were investigated by laboratory X-ray diffraction (XRD), synchrotron XRD, polarized Raman spectroscopy, and Raman mapping. XRD results indicated that the EFG substrates had superior crystallinity and high uniformity. Position-dependent XRD ω-rocking curves recorded across a 50.8-mm-diameter substrate had small standard deviations of δF = 1.6% for the full width at half maximum and δP = 2.8% for the peak intensity. The radius of curvature was measured to be 37.7 m for the ( 2 ¯ 01 ) substrate and 16.4 m for the (010) substrate. The results of synchrotron XRD with various beam sizes suggested that the curving of crystal planes was mainly along the [010] growth direction rather than along the [102] direction. Raman spectra showed that Sn doping up to 3.3 × 1018 cm−3 did not give rise to a notable Raman peak shift. The strain distribution evaluated by Raman mapping implied the high uniformity of both ( 2 ¯ 01 ) and (010) substrates. From these results, it was concluded that β-Ga2O3 ingots grown by EFG have high crystallinity and can be treated as three-dimensionally uniform bulk crystals in the cases of both undoped and Sn-doped growth.

X-ray diffraction and Raman characterization of β-Ga2O3 single crystal grown by edge-defined film-fed growth method

Basal plane bending of on- and off-axis 4H-SiC substrates was measured by high-resolution X-ray diffractometry (HRXRD). In order to evaluate basal plane bending properties in detail, line scans of 0004 reflection rocking curves were carried out on the (0001) Si face along the , , , , and directions. The silicon face of unintentionally doped 4H-SiC substrates is not a flat plane. One of them has a “basin”-like concave bend and the other has a “spherical” concave bend. The silicon face of on-axis n-type SiC is also not flat, but approximately convex “spherical”. In contrast, the silicon face of off-axis n-type SiC is “saddle”-like. Bending inheritance of unintentionally doped 4H-SiC and the effect of annealing and corrosion on their bending properties were studied. Molten KOH defect selective etching was carried out to understand the mechanism responsible for the bending. Finally, the effect of single crystal-growth thermal field and structural defects on basal plane bending of the substrates were explored.

Spatial variation of lattice plane bending of 4H-SiC substrates

The growth of large diameter silicon carbide (SiC) crystals produced by the physical vapor transport (PVT) method is outlined. Methods to increase the crystal diameters, and to turn these large diameter crystals into substrates that are ready for the epitaxial growth of SiC or other non homogeneous epitaxial layers are discussed. We review the present status of 150 mm and 200 mm substrate quality at Cree, Inc. in terms of crystallinity, dislocation density as well as the final substrate surface quality.

Jyothi Ambati

Papers

Bulk Growth of Large Area SiC Crystals