Preparation and characterization of high‐k aluminium nitride (AlN) thin film for sensor and integrated circuits applications

Abstract

AbstractIn last years considerable interest has been shown in aluminium nitride (AlN) films because of their optical, electrical, dielectric and acoustic properties. Owing to these characteristics, AlN thin films are suitable for the use in micro‐electronic applications. In this work, AlN thin films were deposited on p‐Si(100) and SiO2/p‐Si(100) substrates by dc reactive magnetron sputtering technique under the same deposition conditions (500 W of discharge power, 30 sccm N2 flow, 80 sccm Ar flow and deposition pressure of 3x10‐3 Pa). These conditions were defined by prior analysis in order to achieve films with smooth surface morphology, hexagonal wurtzite phase, and refractive index compatible with polycrystalline AlN films (between 2.0 and 2.2). The films were physically characterized using a variety of techniques such as atomic force microscopy (AFM), X‐ray diffraction spectroscopy (XRD), Fourier infrared spectroscopy (FTIR) and ellipsometry. Electrical characteristics of films were compared by using metal‐insulator‐semiconductor (MIS) structures. Using a set of metal insulator semiconductor field effect transistors (MISFETs) and electrolyte‐insulator‐semiconductor field effect transistors (EISFETs) fabricated, electrical characteristics and sensing properties were investigated. The electrical quality of the AlN film and AlN/SiO2/p‐Si interface obtained suggests that AlN is an adequate insulator on silicon device and pH sensors application (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)