Effects of substrate self-bias and nitrogen flow rate on non-polar AlN film growth by reactive sputtering

Kota Tatejima, Takahiro Nagata, Keiji Ishibashi, Kenichiro Takahashi, Setsu Suzuki, Atsushi Ogura, Toyohiro Chikyow

Research output: Contribution to journalArticlepeer-review

Abstract

The effects of the N2 gas flow ratio and the substrate self-bias of reactive sputtering on the polarity of AlN film on various planar sapphire substrates were investigated to obtain a non-polar oriented AlN film. On a c-plane sapphire substrate, substrate self-bias enhanced c-plane AlN growth and Al termination at the surface, as confirmed by X-ray diffraction (XRD) and time-of-flight low-energy atom scattering spectroscopy. In addition, the AlN film deposited at an N2 gas:Ar sputtering gas ratio of 14% with substrate self-bias had high crystallinity with an XRD ω-rocking curve of 17 arcsec for the 0002 diffraction. In contrast, the AlN films on a- and r-plane sapphire substrates had semi-polar and non-polar plane orientations, respectively. However, on the a-plane sapphire substrate, the c-plane-orientated AlN phase was also observed, which was increased under substrate self-bias condition and an N2 flow rate below 30%. Preferable conditions for non-polar AlN growth by reactive sputtering were non-substrate self-bias and a high N2 flow rate of 30% or more.

Original languageEnglish
Article numberSDDG07
JournalJapanese journal of applied physics
Volume58
Issue numberSD
DOIs
Publication statusPublished - 2019

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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