The influence of thickness and ammonia flow rate on the properties of AlN layers

• Published in: Materials science in semiconductor processing 2012-02, Vol.15 (1), p.32-36
• Main Authors: Aoerekci, S, Azturk, M K, Aakmak, M, Azcelik, S, Azbay, E
• Format: Article
• Language: English
• Subjects: AlN thin films; Aluminum nitride; Ammonia; Ammonia flow rate; Applied sciences; Asymmetry; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Crystallinity; Diffraction; Electronics; Exact sciences and technology; Flow rate; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Microelectronic fabrication (materials and surfaces technology); Physics; Planes; Scanning probe microscopes, components and techniques; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Semiconductors; Solid surfaces and solid-solid interfaces; Surface structure and topography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 1369-8001; 1873-4081
• DOI: 10.1016/j.mssp.2011.06.003

Undoped AlN layers have been grown on c-plane sapphire substrates by metal-organic chemical vapor deposition in order to study the effects of ammonia (NH3) flow rate and layer thickness on the structural quality and surface morphology of AlN layers by high-resolution X-ray diffraction, scanning electron microscopy, and atomic force microscopy. Lower NH3 flow rate improves crystallinity of the symmetric (0002) plane in AlN layers. Ammonia flow rate is also correlated with surface quality; pit-free and smooth AlN surfaces have been obtained at a flow rate of 70 standard cm3 per minute. Thicker AlN films improve the crystallinity of the asymmetric (101̄2) plane. ► Low ammonia (NH3) flow rate improves crystallinity of the symmetric (0002) plane in AlN layers. ► Low NH3 flow rate also leads pit-free and smooth AlN surfaces. ► Thick-layer growth improves the crystallinity of the asymmetric (101̄2) plane in AlN layers.