Simulation for 3-D optical and electrical analysis of CCD

A device simulator, SPECTRA, and an optics simulator, TOCCATA, were developed for three-dimensional (3-D) optical and electrical analysis of a charge-coupled device (CCD). SPECTRA solves Poisson's and time dependent current continuity equations by a novel Gummel's method. Since the basic parameters are potential and exponential functions of the quasi-Fermi level of electrons and holes, the solution can be obtained in a stable and rapid way compared to the conventional method. TOCCATA calculates the shape of layers, which consist of silicon-oxide, silicon-nitride, poly-silicon, light shield metal, micro-lens material, etc., formed on a silicon substrate and performs ray tracing on multiple reflection, refraction, and absorption or executes wave analysis which involves interference and diffraction. The combination of these simulators realizes the optical and electrical analysis for the total design of CCD cell structures on and in a silicon substrate. It is reported that the simulation method successfully analyzes the optical and electrical characteristics of interline-transfer charge-coupled devices (IT-CCD).