Laser-Induced Fluorescence Observation of In-Atoms Produced by DC Reactive Sputtering of Indium-Tin-Oxide Target

Abstract

Spatial density profiles of sputtered In-atoms in a dc glow discharge with an indium-tin-oxide (ITO) cathode were measured by laser-induced fluorescence (LIF) spectroscopy. The absolute density of In-atoms was obtained by calibrating the LIF signal with the Rayleigh scattering signal for Ar. The spatial density profile of In-atoms had a peak at a certain distance from the cathode, and this peak density was about 1011 cm-3 for pure Ar dc discharge at 0.2 Torr and 0.6 Wcm-2. The behavior of spatial profiles of the absolute In-density was investigated as a function of dc discharge power, total pressure ( Ar+O2), and O2 partial pressure. Addition of a small amount of O2 caused a drastic change in both the absolute In-density and its spatial distribution. From these observations, the reactive sputtering mechanism in a dc glow discharge is discussed.