Effects of Post-Annealing on the Conduction Properties of Pt/(Ba, Sr)TiO 3 /Pt Capacitors for Dynamic Random Access Memory Applications

• Published in: Japanese Journal of Applied Physics 1997-07, Vol.36 (7R), p.4382
• Main Authors: Joo, Jae-Hyun, Jeon, Yoo-Chan, Seon, Jeong-Min, Oh, Ki-Young, Jae-Sung Roh, Jae-Sung Roh, Jae-Jeong Kim, Jae-Jeong Kim
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.36.4382

Pt/(Ba, Sr)TiO 3 /Pt capacitors were fabricated on TiN/Ti/ Poly –Si/SiO 2 /Si substrate by sputtering technique and effects of post-annealing conditions on the current vs. voltage ( I–V ) characteristics of the capacitors were investigated. It was found that leakage currents of Pt/BST/Pt capacitors were greatly depended on the annealing sequence as well as annealing atmosphere. BST films annealed under Ar/H 2 or N 2 showed much higher leakage current than as-deposited films regardless of the fabrication of top electrode. On the contrary, annealing under O 2 atmosphere was effective to reduce leakage currents of the BST films if annealing process was carried out after fabrication of top electrode. Leakage current of Pt/BST(50 nm)/Pt capacitors annealed under O 2 atmosphere at 500° C for 1 h after fabrication of Pt top electrode was 5×10 -7 A/cm 2 even at 7 V. In this work, effects of annealing conditions on the I–V properties of Pt/BST/Pt capacitors were explained with energy band diagram in which oxygen vacancies play a key role.