Electrical Properties of ZrO2/Al2O3/ZrO2‐Based Capacitors with TiN, Ru, and TiN/Ru Top Electrode Materials. Issue 10 (24th August 2018)

• Record Type: Journal Article
• Authors: Lee, Woongkyu; An, Cheol Hyun; Yoo, Sijung; Jeon, Woojin; Chung, Min Jung; Kim, Sang Hyeon; Hwang, Cheol Seong
• Is Part Of: Physica status solidi. Volume 12:Issue 10(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-08-24
• Subjects: dielectric layers -- DRAM capacitors -- electrodes -- metal/insulator/metal structures -- Ru -- TiN -- ZAZ; Solid state physics -- Periodicals; 530.4105
• DOI: 10.1002/pssr.201800356
• Languages: English
• ISSNs: 1862-6254

Abstract

Abstract : To improve the electrical properties of metal/insulator/metal capacitors for dynamic random access memory, the effects of the top electrode materials and their structures on the capacitor performance are examined. Three kinds of top electrode types (TiN, Ru, and TiN/Ru) are sputter‐deposited on ZrO2 /Al2 O3 /ZrO2 (ZAZ) dielectric layers grown via atomic layer deposition (ALD) on TiN bottom electrodes. The TiN/Ru top electrode samples show the highest capacitance density among the three types of top electrodes, and the Ru and TiN/Ru top electrodes show less leakage current density than the TiN top electrode. The interface property is optimized when the Ru directly contacts the insulating layer due to its higher work function. The TiN layer on the 2 nm‐thick Ru top electrode decreases the adverse interfacial reaction layer (TiOx Ny ) of the dielectric/TiN bottom electrode through the scavenging oxygen atoms. Abstract : Three kinds of top electrode types (TiN, Ru, and TiN/Ru) are prepared for ZrO2 /Al2 O3 /ZrO2 ‐based capacitors for DRAM applications. Although capacitors with TiN and Ru top electrodes have adverse interfacial property at the top and bottom of the dielectric layer, respectively, the TiN/Ru top electrode induces clean interfaces at both sides of the ZrO2 /Al2 O3 /ZrO2 layer. Moreover, the leakage current density decreases as the thin Ru layer with higher work function directly contacts the dielectric layer.