Insulating layers of polycrystalline GaAsS compounds grown by reactive plasma sputtering

• Published in: Thin solid films 1999-01, Vol.337 (1), p.184-187
• Main Authors: Pesty, O, Canet, P, Lalande, F, Seguin, J.L, Carchano, H
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical 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; Physics; Polycrystalline GaAsS; Reactive plasma sputtering
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/S0040-6090(98)01198-5

GaAsS ternary compounds are obtained from reactive radio-frequency cathodic sputtering of a monocrystalline gallium arsenide target in an argon and sulfurous hydrogen plasma. Thin films deposited on temperature controlled molybdenum substrates enable us to obtain a sandwich structure: Au/GaAsS/Mo. Electrical (current–voltage) characterizations show a change, with sulfur concentration, in the compound behavior, from a highly doped semiconductor to a heavily insulating material. Maximum serial resistivity (3×10 14 Ω cm) is attained with a sulfur concentration of 50% (arsenic concentration being nearly 0%) and a typical space-charge-limited (SCL) conduction is obtained. We determine dielectric permitivity from capacitative measurements. This material presents insulating properties (varying with sulfur concentration) equivalent to those of SiO 2 compounds. Moreover epitaxial layers can be grown on GaAs substrate, which will lead to applications in GaAs technologies as an insulator or an interface (depending on lattice parameter).