A Simulation Study of Electronic Device Designs for the Control of SiC Color Centers as Spin Qubits

Abstract:

Point defects in 4H silicon carbide (4H-SiC), such as the silicon vacancy, also known as color centers, offer considerable potential for quantum applications in the fields of quantum sensing as well as computing and communication. The latter two necessitate indistinguishable photons for entanglement swapping and consequently demand precise control over the electronic transition energies, i.e. emission and absorption wavelengths of color centers. One way to achieve this is through monolithic integration of electronic devices in combination with integrated photonics in 4H-SiC. This is considered a potential pathway for scalable quantum photonic integrated circuits. In this paper, we investigate the suitability of a signal-ground-modulator and a vertical pin diode in combination with a waveguide to (i) achieve local field strengths of 5 to 20 MV/m in the crystal’s c-direction, (ii) stabilize the charge state of the silicon vacancy by controlling the local Fermi level, (iii) meet the requirements for photonic single-mode operation, and (iv) minimize the absorption of the evanescent wave due to metal contacts. The findings of the electronic and optical simulations conducted with Synopsys Sentaurus and Ansys Lumerical suggest that the signal-ground-modulator, commonly used in integrated photonics, rarely attains the requisite field strength. In contrast, the vertical pin diode has the potential to meet these requirements even at reduced bias voltages. Furthermore, the intrinsic layer of the diode offers a wide region in which to host the color center in its optically active, negatively charged state.

• Periodical: Key Engineering Materials (Volume 1056)
• Pages: 33-40
• DOI: https://doi.org/10.4028/p-34PxQw
• Online since: May 2026
• Authors: Fabian J. Magerl*, Christophe Pixius, Julietta Förthner, Patrick Berwian, Eberhard Bär, Jörg Schulze
• Keywords: 4H-SiC, Color Centers, Quantum Applications, Qubits, TCAD Simulations

References

[1] S. Castelletto and A. Boretti, Silicon carbide color centers for quantum applications, J. Phys. Photonics, vol. 2, no. 2, p.22001, 2020.

DOI: 10.1088/2515-7647/ab77a2

[2] H. Bernien et al., Heralded entanglement between solid-state qubits separated by 3 meters, Nature, vol. 497, no. 7447, pp.86-90, 2013.

DOI: 10.1038/nature12016

[3] M. Rühl et al., Stark Tuning of the Silicon Vacancy in Silicon Carbide, Nano letters, vol. 20, no. 1, pp.658-663, 2020.

DOI: 10.1021/acs.nanolett.9b04419

[4] C. F. de las Casas et al., Stark tuning and electrical charge state control of single divacancies in silicon carbide, Applied Physics Letters, vol. 111, no. 26, 2017, doi: 10.1063/1.5004174.[5] C. P. Anderson et al., Electrical and optical control of single spins integrated in scalable semiconductor devices, Science (New York, N.Y.), vol. 366, no. 6470, pp.1225-1230, 2019.

DOI: 10.1126/science.aax9406

[6] R.-Z. Fang et al., Experimental Generation of Spin-Photon Entanglement in Silicon Carbide, Phys. Rev. Lett., vol. 132, no. 16, 2024.

DOI: 10.1103/PhysRevLett.132.160801

[7] G. Moody et al., 2022 Roadmap on integrated quantum photonics, J. Phys. Photonics, vol. 4, no. 1, p.12501, 2022.

DOI: 10.1088/2515-7647/ac1ef4

[8] D. Scheller et al., Quantum-enhanced electric field mapping within semiconductor devices, Phys. Rev. Applied, vol. 24, no. 1, 2025.

DOI: 10.1103/pv13-vgcw

[9] D. M. Lukin et al., Spectrally reconfigurable quantum emitters enabled by optimized fast modulation, npj Quantum Inf, vol. 6, no. 1, 2020.

DOI: 10.1038/s41534-020-00310-0

[10] C. Babin et al., Fabrication and nanophotonic waveguide integration of silicon carbide colour centres with preserved spin-optical coherence, Nature materials, vol. 21, no. 1, pp.67-73, 2022.

DOI: 10.1038/s41563-021-01148-3

[11] Y. Xue et al., Selective generation of V2 silicon vacancy centers in 4H-silicon carbide, Nano Letters, vol. 24, no. 7, pp.2369-2375, 2024.

DOI: 10.1021/acs.nanolett.3c03905

[12] M. E. Bathen et al., Electrical charge state identification and control for the silicon vacancy in 4H-SiC, npj Quantum Inf, vol. 5, no. 1, 2019.

DOI: 10.1038/s41534-019-0227-y

[13] J. H. Schwarberg et al., Investigation of CMOS Single Process Steps on 4H-SiC a-Plane Wafers for Quantum Applications, 2024, 47th MIPRO ICT and Electronics Convention (MIPRO). IEEE, 2024.

DOI: 10.1109/MIPRO60963.2024.10569589

[14] Sentaurus™ Process User Guide, Version X-2025.06, Synopsys Inc., 2025.

[15] M. E. Bathen et al., First-principles calculations of Stark shifts of electronic transitions for defects in semiconductors: the Si vacancy in 4H-SiC, Journal of physics. Condensed matter : an Institute of Physics journal, vol. 33, no. 7, p.75502, 2020.

DOI: 10.1088/1361-648X/abc804

[16] R. Nagy et al. High-fidelity spin and optical control of single silicon-vacancy centres in silicon carbide, Nat Commun 10, 1954 (2019).

DOI: 10.1038/s41467-019-09873-9

[17] P. Udvarhelyi et al., Spectrally Stable Defect Qubits with no Inversion Symmetry for Robust Spin-To-Photon Interface, Phys. Rev. Appl., vol. 11, no. 7, p.044022.

DOI: 10.1103/PhysRevApplied.11.044022

[18] R. Nagy et al., Narrow inhomogeneous distribution of spin-active emitters in silicon carbide, Applied Physics Letters, vol. 118, no. 14, p.46, 2021.

DOI: 10.1063/5.0046563

[19] M. Widmann et al., Electrical charge state manipulation of single silicon vacancies in a silicon carbide quantum optoelectronic device, Nano letters, vol. 19, no. 10, pp.7173-7180, 2019.

DOI: 10.1021/acs.nanolett.9b02774

[20] Lumerical Inc.

[21] A. May et al., A 4H-SiC CMOS technology enabling smart sensor integration and circuit operation above 500 C, 2024 Smart Systems Integration Conference and Exhibition (SSI). IEEE, 2024.

DOI: 10.1109/SSI63222.2024.10740550

[22] S. M. Sze and K. K. Ng, Physics of Semiconductor Devices: Wiley, 2006.

DOI: 10.1002/0470068329