Structure and Electrical Properties of Sputter Deposited (Ba[sub 1−x],Sr[sub x])(Ti[sub 1−y],Zr[sub y])O[sub 3] Thin Films

Abstract

Ba 1Ϫx ,Sr x )(Ti 1Ϫy ,Zr y )O 3 thin films as the dielectric materials for gigabit-scale dynamic random access memory was deposited by radio frequency magnetron sputtering. The films with controlled compositions were grown from a single target by the control of chamber pressure. When chamber pressure decreased, the dielectric constant of films decreased due to an increase of Zr content. The (Ba 1Ϫx ,Sr x )(Ti 1Ϫy ,Zr y )O 3 thin films prepared in this study show a dielectric constant of 380 ϳ 525 at 100 kHz. The films showed the decrease of leakage current as chamber pressure decreased and the leakage current density of films deposited above 10 mTorr was 10 Ϫ7 ϳ 10 Ϫ8 A/cm 2 at 200 kV/cm. The dominant transport mechanism of films was the interface limited Schottky emission conduction. The (Ba 1Ϫx ,Sr x )(Ti 1Ϫy ,Zr y )O 3 thin film appeared to be potential dielectric material for high density dynamic random access memory.