Microstructure and growth kinetics of nanocrystalline diamond films deposited in large area/low temperature distributed antenna array microwave-plasma reactor

• Published in: Physica status solidi. A, Applications and materials science Vol. 212; no. 11; pp. 2611 - 2615
• Main Authors: Baudrillart, Benoît, Bénédic, Fabien, Brinza, Ovidiu, Bieber, Thomas, Chauveau, Thierry, Achard, Jocelyn, Gicquel, Alix
• Format: Journal Article
• Language: English
• Published: Weinheim Blackwell Publishing Ltd 01.11.2015; Wiley Subscription Services, Inc; Wiley
• Subjects: Antenna arrays; Chemical and Process Engineering; Deposition; diamond; Diamond films; Diamonds; Engineering Sciences; Gas pressure; growth; Materials; microstructure; Microwaves; nanocrystalline materials; Nanocrystals; plasma-enhanced chemical vapor deposition; Substrates; thin films
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.201532276

In this paper, we investigate a new distributed antenna array PECVD system, with 16 microwave plasma sources arranged in a 2D matrix, which enables the growth of 4‐inch diamond films using H2/CH4/CO2 gas mixture at low gas pressure, typically below 0.45 mbar, and at substrate temperature of 400 °C. The influence of substrate position with respect to elementary microwave sources is investigated for three sets of gas pressures in order to improve the diamond growth process in this low temperature/large area deposition setup. Results show that the nanocrystalline diamond films are formed of polycrystalline globular aggregates of 50–200 nm in size, depending on growth conditions, composed of diamond grains around 10–20 nm. An optimal deposition condition corresponding to a pressure of 0.45 mbar and a distance between substrate and microwave sources of 65 mm can be found. In these conditions, highest growth rate (60 nm h−1) with good nanocrystalline features, i.e. smallest grain size (10 nm) and lowest roughness (around 15 nm), is obtained.