Effects of substrate self-bias and nitrogen flow rate on non-polar AlN film growth by reactive sputtering. (21st May 2019)

• Record Type: Journal Article
• Authors: Tatejima, Kota; Nagata, Takahiro; Ishibashi, Keiji; Takahashi, Kenichiro; Suzuki, Setsu; Ogura, Atsushi; Chikyow, Toyohiro
• Is Part Of: Japanese journal of applied physics. Volume 58:Number SD(2019)
• Publication Date: 2019-05-21
• Subjects: Physics -- Periodicals; 621.05
• DOI: 10.7567/1347-4065/ab088f
• Languages: English
• ISSNs: 0021-4922

Abstract

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.