Effect of rapid thermal annealed TiN barrier layer on BST capacitors prepared by RF magnetron cosputter system at low substrate temperatures

This work reports on rapid-thermal-annealed TiN as a barrier for Pt/BST/Pt/ TiN/Ti/Si capacitors. Experimental results indicate that the diffusion of T i and Si from the Ti adhesion layer and Si plug, respectively, degrade the capacitor for the gigabit dynamic random access memories (DRAMs) using bari um strontium titanate (BST) as a dielectric material. Although the diffusio n barrier TiN between the bottom electrode Pt and Ti adhesion layer has bee n conventionally used to release the issue, the interdiffusion of Ti and Si occurs due to the thermal budget of the BST deposition. A rapid thermal an nealing process is applied to the as-deposited TiN barrier against the inte rdiffusion. Excellent electrical characteristics, including high dielectric constant (epsilon (r) = 320), low leakage current (1.5 x 10(-8) A/cm(2)) u nder 0.1 MV/cm, and a lifetime greater than 10 years under 1.5 MV/cm are ob tained. Our results further demonstrate that the proposed technique is high ly promising for future high-density DRAMs. (C) 2000 The Electrochemical So ciety. S1099-0062(00)07-005-X. All rights reserved.