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Eutectic Formation, V/III Ratio, and Controlled Polarity Inversion in Nitrides on Silicon
Author(s) -
Roshko Alexana,
Brubaker Matt D.,
Blanchard Paul T.,
Harvey Todd E.,
Bertness Kris A.
Publication year - 2020
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201900611
Subject(s) - eutectic system , materials science , inversion (geology) , silicon , polar , epitaxy , molecular beam epitaxy , polarity (international relations) , nitride , crystallography , silicon nitride , optoelectronics , chemistry , nanotechnology , microstructure , geology , composite material , layer (electronics) , biochemistry , physics , structural basin , astronomy , paleontology , cell
The crystallographic polarity of AlN grown on Si(111) by plasma‐assisted molecular beam epitaxy is intentionally inverted from N‐polar to Al‐polar at a planar boundary. The position of the inversion boundary is controlled by a two‐step growth process that abruptly changes from Al‐rich to N‐rich growth conditions. The polarity inversion is induced by the presence of Si, which is incorporated from an Al–Si eutectic layer that forms during the initial stages of AlN growth and floats on the AlN surface under Al‐rich growth conditions. When the growth conditions change to N‐rich, the Al and Si in the eutectic react with the additional N‐flux and are incorporated into the solid AlN film. Relatively low levels of Al–Si eutectic formation combined with lateral variations in the Si incorporation lead to nonuniformity in the polarity inversion and formation of surprisingly narrow, vertical inversion domains. The results suggest that intentional incorporation of uniform layers of Si may provide a method for producing polarity engineered nitride structures.