Study of Dry Oxidation of Aluminum Nitride on Si(111) Substrate Grown by Metalorganic Chemical Vapor Deposition

Abstract

We have investigated the dry oxidation behavior of an AlN epilayer on Si(111) substrate by metalorganic chemical vapor deposition (MOCVD) at different temperatures and different oxidation times through XRD analysis and scanning electron microscopy (SEM). The AlN epilayer has been completely oxidized into polycrystalline α- Al 2 O 3 after oxidation at 1100°C for 2 h. The ratio of O 2 to N 2 introduced into the furnace has an influence on the structure of α- Al 2 O 3. There are only α- Al 2 O 3 (104), (113) diffraction peaks in the XRD curve if the O 2: N 2 is lower than 0.2:1. At the temperature over 1100°C, the oxidation is initiated with a rapid oxidation process, followed by a relatively slow process. These two oxidation stages are respectively related to the interfacial reaction mechanism and the diffusion mechanism.