Investigation of the reflow behavior of GeO/sub 2/-SiO/sub 2/ glasses deposited by plasma enhanced chemical vapor deposition

Summary form only given. Plasma Enhanced Chemical Vapor Deposition (PECVD) of mixed GeO/sub 2/-SiO/sub 2/ glass films in a horizontal tube reactor using germane, silane and oxygen has been studied. Film synthesis was carried out at 200°C using a dual coil inductively coupled plasma system. It was determined that the presence of SiH/sub 4/ was not necessary to catalyze the decomposition of GeH/sub 4/ as required in a strictly thermal environment. Quantitative analysis of oxide film composition has been determined using Energy Dispersive X-Ray Spectroscopy (EDS). Charging effects usually observed in nonconducting films have been eliminated with the use of an Environmental Scanning Electron Microscope (N-SEM) operating at a partial pressure of 150 mtorr of oxygen. EDS results indicate that the on wafer and wafer-to-wafer compositional uniformity was ±5% in a caged boat using 4 inch silicon wafers. It was also determined that the Si/Ge ratio content in the solid phase was always less than the Si/Ge ratio in the gas phase by a small amount. Cross-sectional scanning electron microscopy has been employed to study the compositional dependency of the flow behavior of the mixed GeO/sub 2/-SiO/sub 2/ glass films over silicon trenches under various ambient atmospheres. Reflows were performed at temperatures ranging from 600°C to 1050°C in various gas ambient atmospheres.