Gallium nitride, usually grown by Metal-Organic Chemical Vapour Deposition or by Molecular Beam Epitaxy is attracting increasing attention in the fields of optoelectronics and power electronics. However, these methods remain expensive because of the equipment’s cost and/or inefficient utilization of gases in the case of MOCVD or the need for ultrahigh vacuum(UHV) in the case of MBE. In addition, they operate at high temperature (usually above 800 °C), compromising the combination of materials having different thermal expansion coefficients. In this work we will compare the results on GaN films obtained via two plasma based processes: i) reactive sputtering of a liquid Ga target by an Ar/N₂ plasma at room temperature [1] and ii) remote plasma chemical vapor deposition using a N_2//H₂ plasma and trimethylgallium in the temperature range of 300 – 600 °C [2]. The two plasma based processes allow us to explore an intermediate pressure regime (0.1 – 1 mbar) between the UHV of MBE and high pressure of MOCVD (500 mbar), with the additional feature of producing reactive species for the growth but also for the in-situ cleaning of the substrates before processing. In the presentation we will compare the growth processes of the two techniques and the resulting optical and structural properties of the films.

 

1. L. Srinivasan et al. J. Vac. Sci. Technol. A. Vol.41, Issue 5 (2023)

2. L. Watrin et. al. Submitted to J. Phys. D. Appl. Phys.