Advances in RF Glow Discharge Optical Emission Spectrometry Characterization of Intrinsic and Boron-Doped Diamond Coatings

abstract

Accurate determination of the effective doping range within diamond thin films is important for fine-tuning of electrical conductivity. Nevertheless, it is not easily attainable by the commonly adopted techniques. In this work, pulsed RF glow discharge optical emission spectrometry (GD-OES) combined with ultrafast sputtering (UFS) is applied for the first time to acquire elemental depth profiles of intrinsic diamond coatings and boron content bulk distribution in films. The GD-OES practical advances presented here enabled quick elemental profiling with noteworthy depth resolution and determination of the film interfaces. The erosion rates and layer thicknesses were measured using differential interferometric profiling (DIP), demonstrating a close correlation between the coating thickness and the carbon/hydrogen gas ratio. Moreover, DIP and the adopted semiquantification methodology revealed a nonhomogeneous bulk distribution of boron within the diamond crystalline structure, i.e., boron doping is both substitutional and interstitial within the diamond framework. DIP measurements also showed that effective boron doping is not linearly correlated to the increasing content introduced into the diamond coating. This is a finding well supported by X-ray diffraction (XRD) Rietveld refinement and X-ray photoelectron spectroscopy (XPS). This work demonstrates the advantage of applying advanced GD-OES operation modes due to its ease of use, affordability, accuracy, and high-speed depth profile analysis capability.

keywords

DEPTH PROFILING ANALYSIS; CVD-DIAMOND; RAMAN-SPECTROSCOPY; FILMS; GROWTH; LAYERS; GDOES; RESOLUTION; CARBON; OXYGEN

subject category

Science & Technology - Other Topics; Materials Science

authors

Sharma, DK; Girao, AV; Chapon, P; Neto, MA; Oliveira, FJ; Silva, RF

Groups

G3 - Electrochemical Materials, Interfaces and Coatings

Projects

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Mobilizar competências tecnológicas em Engenharia de Superficies (ON-SURF)

acknowledgements

This work was financed by national funds from the Portuguese Foundation for Science and Technology/MCTES within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, and project On-SURF, POCI-01-0247-FEDER-024521, co-financed via FEDER, under the PT2020 Partnership Agreement. D.K. Sharma would like to thank project On-SURF for postdoctoral contract (BPD/UI50/7841/2019), and also acknowledges the European projects CZ.02.1.01/0.0/0.0/16_019/0000760 (SOLID21), CZ.02.1.01/0.0/0.0/15 003/0000464 (CAP) and GAAV mobility project no. CSIR-21-4. The research contract of A.V.G. and M.A.N. are funded by national funds (OE), through FCT.Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19.The research contract of A.V.G. and M.A.N. are funded by national funds (OE), through FCT-Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19.