• Ohi, Akihiko
• Ogura, Atsushi
• Nabatame, Toshihide
• Onaya, Takashi
• Sawada, Tomomi
• Kurishima, Kazunori
• Sawamoto, Naomi
• Chikyow, Toyohiro

Abstract

<jats:p>We studied characteristic of Metal-Insulator-Metal capacitors with ZrO<jats:sub>2</jats:sub>/high-<jats:italic>k</jats:italic>/ZrO<jats:sub>2</jats:sub> (Z/high-<jats:italic>k</jats:italic>/Z)-nanolaminate dielectric layers and TiN electrodes. Amorphous Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>, (Ta/Nb)O<jats:sub>x</jats:sub> (TN) and (Ta/Nb)O<jats:sub>x</jats:sub>-Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> (TNA) as high-<jats:italic>k</jats:italic> interlayer were prepared by atomic layer deposition and post-deposition annealing. The dielectric constant (<jats:italic>k</jats:italic>) of ZrO<jats:sub>2</jats:sub> thin film exhibited about 28 because of tetragonal, orthorhombic and cubic phases. The <jats:italic>k</jats:italic> value of Z/high-<jats:italic>k</jats:italic>/Z-nanolaminate dielectric layer is high in order of ZTNZ &gt; ZTNAZ &gt; ZAZ due to the dependence of each <jats:italic>k</jats:italic> value of Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> (~ 9) and TN (~29). The ZTNAZ layer exhibited lowest<jats:italic> </jats:italic>leakage current density of 10<jats:sup>-8</jats:sup> ~ 10<jats:sup>-7</jats:sup> A/cm<jats:sup>2</jats:sup> at 0.6 V compared to those of ZAZ and ZTNZ in CET ~ 1.1 nm. We found that the leakage current property of Z/high-<jats:italic>k</jats:italic>/Z layer is influenced by not only amorphous structure but also band gap width (conduction band offset of ZrO<jats:sub>2</jats:sub>) of high-<jats:italic>k</jats:italic> interlayer. We conclude that the TNA material is one of the candidate material as high-<jats:italic>k</jats:italic> interlayer for future DRAM.</jats:p>

Topics

• density
• impedance spectroscopy
• amorphous
• phase
• thin film
• dielectric constant
• annealing
• current density
• tin
• atomic layer deposition