IEEE Transactions on Electron Devices · 1989 · 48 citations · 2 references
EngineeringElectrical EngineeringMaterials ScienceMicroelectronicsSemiconductor DevicesThin FilmsMemory DevicesOxide SemiconductorsSemiconductor Device MaterialsSemiconductor Thin FilmsThin-film DepositionThin-film MaterialsDielectric ConstantElectrode FabricationGate Oxide LeakageLeakage Current ReductionSputteringSputtering ProcessesThin-film ElectrodesVlsi Implementation
Key techniques for applying Ta/sub 2/O/sub 5/ film to megabit-class MOS DRAMs are presented. A high-purity (4N and up) Ta sputtering target is developed to obtain high-purity Ta/sub 2/O/sub 5/ film. The leakage current in Ta/sub 2/O/sub 5/ film that is deposited using a clean sputtering system with this high-purity target is far lower than that of film deposited with a conventional target. A previous drawback of Ta/sub 2/O/sub 5/, the decrease of effective dielectric constant as thickness decreases, is solved by using Mo as an electrode material. The leakage current increase that results from using metal as a bottom electrode is suppressed by reducing the electrode asperity. MOS DRAMs of up to 16-Mb capacity can be attained without trench technology by using these techniques.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
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