Integrated circuit capacitors having composite titanium oxide and tantalum pentoxide dielectric layers therein

摘要

Methods of forming integrated circuit capacitors (e.g., DRAM capacitors) include the steps of forming a first capacitor electrode (e.g., polysilicon electrode) on a substrate and then forming a titanium nitride layer on the first capacitor electrode. A tantalum pentoxide dielectric layer is then formed on an upper surface of the titanium nitride layer. A step is then performed to convert the underlying titanium nitride layer into a titanium oxide layer. A second capacitor electrode is then formed on the tantalum pentoxide layer. The step of converting the titanium nitride layer into a titanium oxide layer is preferably performed by annealing the tantalum pentoxide layer in an oxygen ambient in a range between about 700° C. and 900° C. This oxygen ambient provides free oxygen to fill vacancies within the tantalum oxide layer and also provides free oxygen which diffuses into the underlying titanium nitride layer.