The Influence of Growth Temperature on the Properties of AlN Films Grown by Atomic Layer Deposition

Abstract

Excellent physical and optical properties of AlN films such as high melting temperature, high thermal conductivity at room temperature, good chemical stability, wide band gap [1, 2] make AlN very promising for several applications such as UV-visible detectors and emitters, optoelectronic displays, and GaAs and silicon carbide passivation [2, 3]. Furthermore, AlN is a suitable candidate for the fabrication of AlxGayIn1−x−yN [3] based electronic and optical device applications. AlN thin films have been grown by using several growth techniques under different growth conditions such as temperature, pressure, precursors, etc. While high-temperature (typically above 1100 ◦C) grown epitaxial AlN films are used in active electronic and optoelectronic device layers, polycrystalline and amorphous AlN films grown at CMOS-compatible temperatures (lower than 300 ◦C) are widely used as dielectric and passivation layers for microelectronic devices [4]. To utilize the full potential of the group III-nitride material system for the mature CMOS technology requires the growth of group III-nitride alloys and heterostructures in the temperature range below 300 ◦C. To overcome the presently encountered limitations for low growth temperatures, plasma enhanced atomic layer deposition (PEALD) of AlN is a promising growth technique which not only reduces the film growth temperature, but also satisfies critical conformality and sub-monolayer thickness control as well [5, 6]. Although the growth of AlN films at different low growth temperatures (100–500 ◦C) has been studied by several groups based on PEALD growth method [7–9], the properties of crys-