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The role of Si in GaN/AlN/Si(111) PAMBE Epitaxy: Polarity and Inversion



Alexana Roshko, Matthew D. Brubaker, Paul T. Blanchard, Todd E. Harvey, Kristine A. Bertness


The microstructure, polarity and Si distribution in AlN/GaN layers grown by PAMBE on Si(111) was assessed by STEM. Samples grown under both metal- and nitrogen-rich conditions contained defects at the AlN/Si interface which suggest formation of an Al-Si eutectic. Correlated with this, interfacial segregation of Si was found in the samples. It is proposed that Si is dissolved in a eutectic layer floating on the AlN surface under metal-rich conditions and that it is incorporated into the film if the growth becomes nitrogen-rich, either intentionally or due to plasma source transients. These Si-rich layers appear to induce inversion of the nitride from nitrogen- to metal-polarity, and uncontrolled variations in the Si concentration cause occasional nonuniformity in the resulting inversion.
Japanese Journal of Applied Physics


AlN, GaN, Si, polarity, inversion, PAMBE, STEM, EDS


Roshko, A. , Brubaker, M. , Blanchard, P. , Harvey, T. and Bertness, K. (2019), The role of Si in GaN/AlN/Si(111) PAMBE Epitaxy: Polarity and Inversion, Japanese Journal of Applied Physics, [online], (Accessed April 14, 2024)
Created May 22, 2019, Updated June 1, 2020