Germanium Nanoparticle Formation into Thin SiO2 Films by Negative Ion Implantation and Their Electric Characteristics

Abstract

Germanium nanoparticles in a thin SiO2 film on Si have been formed by negative ion implantation for the development of very low power consumption electron devices using nanoparticles. Their electrical properties of 25‐nm‐SiO2/Si films including Ge nanoparticles were investigated with CV method after subsequent annealing at various temperatures. Ge atoms were implanted at 10 keV with fluencies of 1×1015 and 5×1015 ions/cm2. Samples were annealed at 300, 500, 700 and 900°C for 1 h. Depth profiles of implanted Ge atoms in the SiO2 films were measured by using a high‐resolution RBS technique. The formed Ge nanoparticles were studied by cross‐sectional TEM observation. After annealing at less than 700°C, Ge nanoparticles were confirmed in the film. After 300°C‐annealing, a CV curve had so small hysteresis that could not be applied to memory devices. After 500°C‐annealing, both samples with 1×1015 ions/cm2 and with 5×1015 ions/cm2 had obvious hysteresis curves. Calculations of charge and nanoparticle intensity ...