Schottky barrier height engineering for next generation DRAM capacitors

DRAM capacitors are reaching the scaling limit and new approaches are necessary to enable further reduction of the physical thickness of the capacitor dielectric. The Schottky Barrier Height (SBH) of a noble metal electrode (Pt) on atomic layer deposited ZrO₂/Al₂O₃/ZrO₂ (ZAZ, 6 nm) was evaluated and compared to a TiN electrode. Internal Photo Emission Spectroscopy (IPE) and Photoconductivity measurement (PC) were used to estimate the SBH and band gap, respectively. The SBH difference between the two electrodes was evaluated in comparison with a previously reported model. Finally, the impact of an increased SBH on dielectric scaling will be discussed based on a leakage current simulation of a ZrO₂ capacitor.