Influence of spark plasma sintering and reaction bonded SiC targets on pulsed laser deposition of 6H-SiC thin films

Fabrication of single-crystal silicon carbide thin films without any impurities is necessary for microelectromechanical systems applications. Pulsed laser deposition (PLD) of silicon carbide thin films combined with annealing can be used to grow 6H-SiC thin films in a vacuum chamber and at lower temperatures than conventional vapor deposition techniques. In the present study, the pulsed laser deposition of 6H-SiC thin films using two different silicon carbide targets and with varying substrate temperatures was investigated. In the PLD process, SiC targets prepared by two different techniques, namely, the reaction bonding technique (Carborundum Universal Limited, India) and the spark plasma sintering (SPS) technique using SiC powder (≈10.2 µm), were used. The thin films were deposited using a Nd3+:YAG (λ = 355 nm, 4 ns) laser source on silicon (1 0 0) substrates in an argon atmosphere. The post-deposited films were annealed at 1000 °C for 30 min to realize 6H-SiC. Deposition at lower temperatures between 800 and 900 °C resulted in a smooth and continuous SiC film growth with an average roughness of 2 nm. The films deposited above 950 °C formed an island pattern on the substrate. The intrinsic films were doped with nitrogen using the laser-assisted doping technique in aqueous ammonia. Electrical resistance in the films deposited with the RB-SiC target was found to be lesser than that deposited with the SPS-SiC target.