The Kyoto Institute of Technology (KIT) has recently turned its attention to a GaN etching process utilizing methane (CH4) plasma, which holds significant promise for reducing environmental impact. In a bid to accelerate practical application, researchers at KIT have been actively exploring the optimal conditions for efficient GaN etching using this CH4 plasma technology.
Currently, GaN etching predominantly relies on chlorine (Cl)-based etching gases. However, this conventional method is associated with several drawbacks, including potential damage to the material, toxicity, and corrosiveness. The push for a safer and more sustainable alternative is paramount in semiconductor manufacturing.
The experimental results from KIT are highly encouraging. The team confirmed that a mixed gas of methane (CH4) and oxygen (O2) is effective for the GaN etching process. The mechanism involves the oxygen (O2) removing excess carbon from the reactor, which in turn allows CHx and hydrogen (H) to act as the primary etchants, facilitating efficient etching.
However, the study also provided a crucial finding regarding the gas mixture ratio. While oxygen (O2) is necessary to clear carbon residue, an excessive amount of oxygen was found to inhibit the etching rate. This is likely due to an insufficient supply of the primary etchants (CHx and H). This research paves the way for a more environmentally friendly and potentially less damaging method for processing GaN devices.
