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.
, Brubaker, M.
, Blanchard, P.
, Harvey, T.
and Bertness, K.
The role of Si in GaN/AlN/Si(111) PAMBE Epitaxy: Polarity and Inversion, Japanese Journal of Applied Physics, [online], https://doi.org/10.7567/1347-4065/ab1124
(Accessed May 19, 2022)