Gallium nitride (GaN) is one of the most important semiconductor materials in modern electronics. While GaN films are routinely deposited by chemical vapor deposition at around 1000 °C, low-temperature routes for GaN deposition need to be better understood. Herein, we present an atomic layer deposition (ALD) process for GaN-based on triethyl gallium (TEG) and ammonia plasma and show that the process can be improved by adding a reactive pulse, a “B-pulse” between the TEG and ammonia plasma, making it an ABC-type pulsed process. We show that the material quality of the deposited GaN is not affected by the B-pulse, but that the film growth per ALD cycle increases when a B-pulse is added. We suggest that this can be explained by the removal of ethyl ligands from the surface by the B-pulse, enabling a more efficient nitridation by the ammonia plasma. We show that the B-pulsing can be used to enable GaN deposition with a thermal ammonia pulse, albeit of x-ray amorphous films.
Surface ligand removal in atomic layer deposition of GaN using triethylgallium
Petro Deminskyi, Chih-Wei Hsu, Babak Bakhit, Polla Rouf, Henrik Pedersen; Surface ligand removal in atomic layer deposition of GaN using triethylgallium. J. Vac. Sci. Technol. A 1 January 2021; 39 (1): 012411. https://doi.org/10.1116/6.0000752
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