Device Degradation on a Full-Frame CCD Image Sensor with a Transparent Gate Electrode

Abstract

ABSTRACTThe electrical and optical properties of Indium-Tin-Oxide (ITO) films, deposited by radio frequency (r.f.) magnetron sputtering, were studied. ITO films, when deposited using optimum sputtering conditions, were reproducibly prepared with resistivity as low as 1.5 × 10−4 Ω-cm and optical transmissivity higher than 80% over the wavelength range of interest. Device stability when ITO is used as a replacement for polysilicon as a gate electrode in silicon charge-coupled device (CCD) image sensors was also studied. After an anneal process at 950 °C in N2 the device degraded. The degradation can be attributed to the generation of oxide charge and interface states in the ITO/SiO2/Si system.