Role of High-k Interlayer in ZrO2/High-k/ZrO2 Insulating Multilayer on Electrical Properties for DRAM Capacitor. (18th August 2016)

• Record Type: Journal Article
• Authors: Onaya, Takashi; Nabatame, Toshihide; Sawada, Tomomi; Kurishima, Kazunori; Sawamoto, Naomi; Ohi, Akihiko; Chikyow, Toyohiro; Ogura, Atsushi
• Is Part Of: ECS transactions. Volume 75:Number 8(2016)
• Page Start: 667
• Page End: 674
• Publication Date: 2016-08-18
• Subjects: Electrochemistry -- Periodicals; Electrochemistry; Periodicals; Electronic journals; Electronic journal; 541.37
• DOI: 10.1149/07508.0667ecst
• Languages: English
• ISSNs: 1938-5862

Abstract

Abstract : We studied characteristic of Metal-Insulator-Metal capacitors with ZrO2 /high- k /ZrO2 (Z/high- k /Z)-nanolaminate dielectric layers and TiN electrodes. Amorphous Al2 O3, (Ta/Nb)Ox (TN) and (Ta/Nb)Ox -Al2 O3 (TNA) as high- k interlayer were prepared by atomic layer deposition and post-deposition annealing. The dielectric constant ( k ) of ZrO2 thin film exhibited about 28 because of tetragonal, orthorhombic and cubic phases. The k value of Z/high- k /Z-nanolaminate dielectric layer is high in order of ZTNZ > ZTNAZ > ZAZ due to the dependence of each k value of Al2 O3 (~ 9) and TN (~29). The ZTNAZ layer exhibited lowest leakage current density of 10 -8 ~ 10 -7 A/cm 2 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- k /Z layer is influenced by not only amorphous structure but also band gap width (conduction band offset of ZrO2 ) of high- k interlayer. We conclude that the TNA material is one of the candidate material as high- k interlayer for future DRAM.