SILICA-BASED OXIDE SYSTEMS .1. EXPERIMENTAL AND CALCULATED PHASE-EQUILIBRIA IN SILICON, BORON, PHOSPHORUS, GERMANIUM, AND ARSENIC OXIDE MIXTURES

Relations between the glass transition, the flow, and the liquidus temperatures were studied in order to determine compositions of silica-rich oxide materials for planarization layers in very large scale integrated technology. Thus, the Si1/2O, B2/3O, P2/5O, Ge1/2O, and As2/3O binary phase diagrams involved were experimentally determined. These binary diagrams were calculated using a polynomial description of the Gibbs free enthalpy of mixing for liquid phases and solid solutions. Ternary and quaternary phase diagrams were then computed in the silica-rich region, giving the liquidus temperatures for selected mixtures. In determining the lowest liquidus temperatures, compositions in the Si1/2O-B2/3O-Ge1/2O and Si1/2O-B2/3O-As2/3O systems have been proposed to obtain low reflow temperatures.