Crystallographic texture study of pulsed laser deposited Cr2O3 thin films

Abstract

Chromium oxide thin films of thickness ~140 nm were grown on c-plane (0001) and a-plane (112¯0) sapphire substrates by Pulsed Laser Deposition (PLD) technique. The films of Cr2O3 on Si (100) substrates have been synthesized at an optimized oxygen partial pressure of 2 Pa with varying substrate temperature in the range of 473-973 K. It was observed that the films deposited at temperatures ≥673 K are crystalline as confirmed by X-Ray Diffraction (XRD) studies. The X-Ray Photoelectron Spectroscopy (XPS) profile showed that the films were grown with Cr3+ oxidation state. Atomic Force Microscopy (AFM) revealed smooth, uniform surface morphology with small amount of porosity. The epitaxial nature of the film on sapphire substrate and crystallographic orientation of the Cr2O3 over Si substrate were studied using rocking curve, ϕ (Phi) scan and pole figure measurement. Pole figure analysis suggested that the films deposited on Si substrate were fiber textured. Rocking curve Full Width at Half Maximum (FWHM) for Cr2O3 (0006) and Cr2O3 (112¯0) was about 0.1° and 0.06° respectively, which indicate the good quality of crystalline film. High Resolution X-ray Diffraction (HRXRD) with reciprocal space mappings (RSM) measurements indicate that the films grown on sapphire substrates are in relaxed state.