Structural, electrical and optical properties of zinc nitride thin films prepared by reactive rf magnetron sputtering

• Published in: Thin solid films 1998-06, Vol.322 (1), p.274-281
• Main Authors: Futsuhara, Masanobu, Yoshioka, Katsuaki, Takai, Osamu
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition by sputtering; Electrical properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport phenomena in thin films and low-dimensional structures; Exact sciences and technology; Low-field transport and mobility; piezoresistance; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Nitride; Optical properties; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Other semiconductors; Physics; Sputtering; Structural properties; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Zinc
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/S0040-6090(97)00910-3

Polycrystalline zinc nitride (Zn 3N 2) thin films are prepared by reactive rf magnetron sputtering with different N 2 concentrations in sputtering gases (N 2–Ar mixtures). Structure and chemical bonding states are measured with X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. Single phase Zn 3N 2 film formation and texture strongly depend on N 2 concentration. Polycrystalline Zn 3N 2 films are formed at N 2 concentrations over 20% and show a 100 preferred orientation. The XPS N 1s peak (395.8 eV) for Zn 3N 2 indicates a large chemical shift of 3.0 eV from the N 1s peak for free amine (398.8 eV) indicative of the formation of N–Zn bonds. Moreover, the modified Auger parameter, which is a good measure of the chemical state, is determined to be 2012.3 eV for Zn 3N 2 from XPS measurements. This value is significantly different from the values for ZnO and metallic zinc. The polycrystalline Zn 3N 2 films show a high electron mobility of about 100 cm 2 V −1 s −1 at room temperature. Zn 3N 2 is determined to be an n-type semiconductor with direct gap of 1.23±0.02 eV.