Controlled stress in germanosilicate glasses deposited by plasma-enhanced chemical vapor deposition

Summary form only given. As structures in integrated microelectronic devices become smaller, there is a need for passivation and interconnection layers that exhibit controllable stress and have good reflow properties at reduced temperatures in order to stay within thermal budgets. One possibility for this material is germanium-silicon oxides, or germanosilicates. Germanosilicate films have been deposited at 200/spl deg/C by Plasma Enhanced Chemical Vapor Deposition utilizing germane, silane, oxygen, and argon in an inductively-coupled plasma generated by twin coils in a horizontal reactor tube. Film composition was varied by altering the germane to silane ratio at constant total flow. Solubility tests in boiling water indicate that the films are stable above 50% SiO/sub 2/. Compositional analysis was performed by Electron Dispersive Spectroscopy (EDS), and was found to be linear with hydride input percentages. Variable Angle Spectroscopic Ellipsometry (VASE) indicates that the index of refraction is roughly linear, although lower than the ideal from bulk samples in all cases. Stress levels were characterized by a single-beam laser cantilever system with the oxides deposited on bare silicon wafers. Results indicate that stress levels are on the order of 10/sup 8/ dynes/cm/sup 2/ for the entire range of germanosilicate films, compressive at pure SiO/sub 2/ and tensile for films of 10% GeO/sub 2/ and higher.