Investigation of Si-nanocrystal memory structures obtained by r.f. sputtering

Currently effects related to carrier confinement in nanometer sized silicon structures are extensively studied. So it has been shown that Si in spite of its indirect band
gap can efficiently emit photons due to carrier recombination provided that low dimensionality is achieved. Further a novel Si-nanocrystal floating gate MOSFET
memory structure has been proposed. In all these applications the formation of Si-quantum dots is a critical step being tackled using a variety of methods. Our
approach is rf magnetron sputtering, a popular thin film preparation technique compatible with conventional Si-technology and providing an elegant way to prepare
device quality SiO2 thin-films, but also SiO2/nanocrystalline (nc)-Si/SiO2 thin-film systems. SiO2 films were prepared by sputtering from an high purity quartz
target and characterized by TEM, FTIR, Current-Voltage and Capacitance-Voltage measurements. The electrical properties of the sputtered oxide films are
comparable to those of thermally grown oxides. By alternate sputtering from Si and SiO2-targets thin-film systems have been prepared. For the latter charge
storage in the nc-Si-floating gate has been demonstrated.