Plasma-enhanced chemical vapour deposition process for depositing silicon nitride or silicon oxynitride, process for producing one such layer arrangement, and layer arrangement

摘要

A plasma-enhanced chemical vapor deposition process for depositing relatively high dielectric constant silicon nitride or oxynitride to form an MIM capacitor is described. The flow rate ratios for the silicon nitride layer are: silane-to-ammonia between 1:20 and 6:5 and silane-to-nitrogen flow between 1:40 and 3:5. A pressure in the process chamber is between 260 Pa and 530 Pa. The flow rate ratios for the silicon oxynitride layer are: silane-to-dinitrogen monoxide between 1:2 and 25:4 and silane-to-nitrogen between 1:100 and 1:10. A larger, non-stoichiometric amount of silicon is incorporated in the layers as the flow rate of the silicon precursor is increased. The layers are deposited in substeps in which the deposition is interrupted between successive substeps. The layer is exposed to an oxygen-containing plasma such that electrically conductive regions of the layer are converted into electrically insulating regions as a result of interaction with the plasma.