Silicon carbonitride (SiCN) is a wide bandgap semiconductor material that has drawn significant interest over the past few decades due to its excellent optical, electrical, and mechanical properties[1]. Rare earth doping in wide bandgap semiconductors has several prospective applications in the field of photoelectric devices, solid-state lasers, flat panel displays, and high-energy radiation detectors [2]. Among the various rare earth materials, europium (Eu) is particularly interesting due to its optically active divalent and trivalent states capable of emitting in different visible spectral ranges [3].

In this work, Eu-doped SiCN thin films were prepared by electron cyclotron resonance plasma-enhanced chemical vapor deposition (ECR-PECVD) with integrated magnetron sputtering [4] on p-type 3” Si (100) substrates. Silane (diluted in 90% argon), nitrogen (diluted in 90% argon) and ethane (C₂H₆) were used as precursor gases, and a 99.9% pure Eu sputtering target was used as a sputtering source. To understand the effect of C incorporation in the Eu-doped SiCN matrix, we have prepared a set of samples without C. The as-deposited samples were annealed over a wide range of temperatures from 600 to 1100° C in an internet N₂ environment. Rutherford backscattering spectrometry (RBS) was performed to determine the atomic concentration of the constituents. Variable angle spectroscopic ellipsometry (VASE) analysis was performed to investigate the optical properties of the films. The room temperature photoluminescence (PL) experiments were carried out with a laser diode excitation source, operating at a wavelength of 375nm. Finally, we performed nanoindentation measurements to understand the deformation behavior of SiCN films as a function of the incorporation of C. The indentation hardness and Young’s modulus of the films were investigated for different Eu and C concentrations.

References:

[1] Q. Li, Y. Wang, X. Shan, X. Wang, and W. Zhao, “Preparation and optical properties of SiCN thin films deposited by reactive magnetron sputtering,” J. Mater. Sci. Mater. Electron., vol. 28, no. 9, pp. 6769–6781, 2017.

[2] Z. Ma, J. Zhou, Z. Chen, and E. Xie, “Luminescence properties of terbium-doped SiCN thin films by rf magnetron reactive sputtering,” Diam. Relat. Mater., vol. 20, no. 4, pp. 475–479, 2011.

[3] X. Zhang, D. Yang, D. Li, and M. Wang, “Intense photoluminescence from Eu-doped silicon-rich silicon oxide films prepared by electron beam evaporation,” IEEE Int. Conf. Gr. IV Photonics GFP, pp. 66–68, 2009.

[4] J. W. Miller, Z. Khatami, J. Wojcik, J. D. B. Bradley, and P. Mascher, “Integrated ECR-PECVD and magnetron sputtering system for rare-earth-doped Si-based materials,” Surf. Coatings Technol., vol. 336, pp. 99–105, 2018.