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High-k dielectrics for future generation memory devices (Invited Paper)

2009; Elsevier BV; Volume: 86; Issue: 7-9 Linguagem: Inglês

10.1016/j.mee.2009.03.045

1873-5568

J. A. Kittl, Karl Opsomer, M. Popovici, N. Menou, B. Kaczer, X. P. Wang, Christoph Adelmann, Małgorzata Pawlak, Kazuyuki Tomida, A. Rothschild, B. Govoreanu, R. Degraeve, Marc Schaekers, M. Zahid, Annelies Delabie, Johan Meersschaut, W. Polspoel, Sergiu Clima, Geoffrey Pourtois, W. Knaepen, Christophe Detavernier, V. V. Afanas’ev, Tom Blomberg, Dieter Pierreux, Johan Swerts, Pamela R. Fischer, Jan Willem Maes, D. Manger, Wilfried Vandervorst, Thierry Conard, Alexis Franquet, Paola Favia, H. Bender, Bert Brijs, Sven Van Elshocht, M. Jurczak, Jan Van Houdt, Dirk J. Wouters,

Ferroelectric and Negative Capacitance Devices

The requirements and development of high-k dielectric films for application in storage cells of future generation flash and Dynamic Random Access Memory (DRAM) devices are reviewed. Dielectrics with k-value in the 9–30 range are studied as insulators between charge storage layers and control gates in flash devices. For this application, large band gaps (>6 eV) and band offsets are required, as well as low trap densities. Materials studied include aluminates and scandates. For DRAM metal–insulator–metal (MIM) capacitors, aggressive scaling of the equivalent oxide thickness (with targets down to 0.3 nm) drives the research towards dielectrics with k-values >50. Due to the high aspect ratio of MIMCap structures, highly conformal deposition techniques are needed, triggering a substantial effort to develop Atomic Layer Deposition (ALD) processes for the deposition of metal gates and high-k dielectrics. Materials studied include Sr- and Ba-based perovskites, with SrTiO3 as one of the most promising candidates, as well as tantalates, titanates and niobates.