Investigations Of The Electrical And Optical Properties Of Rf Sputtered Bismuth Oxide Thin Films

Low temperature preparation of thin amorphous Silicon Nitride and Germanium Films by direct RF sputter deposition was investigated. Influence of various sputtering parameters on film properties was studied. Infrared transmission spectrophotometry was used to evaluate optical properties of the films whereas electrical characteristics of the films were determined from current-voltage measurements of MIS structures. For Silicon Nitride films it was observed that the stoichiometry, as indicated by the IR transmission, dielectric constant and current density versus square root of electric field measurements, was a strong function of the sputtering gas composition and particularly the Ar/N ratio in the sputtering gas. It was established from the current-voltage relationship that the dominant conduction mechanism in these films is of PooleFrenkel type. The current-voltage characteristics of the MIS devices were observed to be independent of the electrode material, device area and the film thickness. It is concluded that the insulating films thus deposited were comparable to those deposited using any other deposition method and is anticipated that due to the low deposition temperatures, sputtering may emerge as a highly potential process for optoelectronic device passivation.

The ever increasing advancements in semiconductor technology and continuous scaling of CMOS devices mandate the need for new dielectric materials with low-k values. The interconnect delay can be reduced not only by the resistance of the conductor but also by decreasing the capacitance of dielectric layer. Also cross-talk is a major issue faced by semiconductor industry due to high value of k of the inter-dielectric layer (IDL) in a multilevel wiring scheme in Si ultra large scale integrated circuit (ULSI) devices. In order to reduce the time delay, it is necessary to introduce a wiring metal with low resistivity and a high quality insulating film with a low dielectric constant which leads to a reduction of the wiring capacitance. Boron carbon nitride (BCN) films are prepared by reactive magnetron sputtering from a B4C target and deposited to make metal-insulator-metal (MIM) sandwich structures using aluminum as the top and bottom electrodes. BCN films are deposited at various N2/Ar gas flow ratios, substrate temperatures and process pressures. The electrical characterization of the MIM devices includes capacitance vs. voltage (C-V), current vs voltage, and breakdown voltage characteristics. The above characterizations are performed as a function of deposition parameters.