AlN thin films deposited by DC reactive magnetron sputtering: effect of oxygen on film growth

¹ Institut des Matériaux Jean Rouxel (IMN – Université de Nantes, UMR CNRS 6502), 2 rue de la Houssinière, BP 322298, 44322 Nantes Cedex 3, France
² Instituto de Física Rosario (CONICET-UNR), 27 de Febrero 210 bis, S2000EZP, Rosario, Argentina
³ Instituto de Desarrollo Tecnológico para la Industria Química (INTEC-UNL), Güemes 3450, S3000GLN, Santa Fe, Argentina
⁴ Physics Department, Atomic Energy Commission of Syria (AECS), 17th Nissan street, Kafar Soh, BP 6091, Damascus, Syria

^a e-mail: javier.garcia-molleja@cnrs-imn.fr

Received: 26 September 2013
Accepted: 3 October 2013
Published online: 15 November 2013

Abstract

Aluminum nitride is a ceramic compound with many technological applications in many fields, for example optics, electronics and resonators. Contaminants play a crucial role in the AlN performance. This paper focuses mainly in the effect of oxygen when AlN, with O impurities in its structure, is grown on oxidized layers. In this study, AlN thin films have been deposited at room temperature and low residual vacuum on SiO₂/Si (1 0 0) substrates. AlN films were grown by DC reactive magnetron sputtering (aluminum target) and atmosphere composed by an argon/nitrogen mixture. Working pressure was 3 mTorr. Film characterization was performed by AES, XRD, SEM, EDS, FTIR, HRTEM, SAED and band-bending method. Our results show that oxidized interlayer imposes compressive stresses to AlN layer, developing a polycrystalline deposition. Indeed, when film thickness is over 900 nm, influence of oxidized interlayer diminishes and crystallographic orientation changes to the (0 0 0 2) one, i.e., columnar structure, and stress relief is induced (there is a transition from compressive to tensile stress). Also, we propose a growth scenario to explain this behaviour.