화학공학소재연구정보센터
Current Applied Physics, Vol.10, No.1, E22-E26, 2010
Physical and electrical characteristics of band-engineered Zr-silicate/SiO2 stacks for tunnel barrier
In this work, we investigated the physical properties of (ZrO2)(x)(SiO2)(1-x) such as band-gap, band-offset, structural stability, and the tunneling characteristics of (ZrO2)(x)(SiO2)(1-x)/SiO2 tunnel barrier with total EOT of 4.5 nm for the application to charge trap memory devices. It was observed that the band-gap and band-offset of (ZrO2)(x)(SiO2)(1-x) can be controlled by changing the composition for (ZrO2)(x)(SiO2)(1-x) films. However, the sensitivity of band-gap and band-offset of (ZrO2)(x)(SiO2)(1-x) films on ZrO2 content was minimal for the cycle ratio of ZrO2:SiO2 above 1:1. The Zr-silicate film with the ZrO2:SiO2 cycle ratio of 1: 7 maintained amorphous even after annealing at 1050 degrees C. However, and Zr-silicate film with the ZrO2:SiO2 cycle ratio of 1:1 and 3:1 were crystallized after annealing at 950 degrees C and 850 degrees C, respectively. The band-engineered tunnel barrier of (ZrO2)(x)(SiO2)(1-x)/SiO2 bi-layer showed enhanced tunnel efficiency at high gate bias, while showed smaller tunnel current at low gate bias than a single SiO2 tunnel barrier of the similar EOT. (C) 2009 Elsevier B.V. All rights reserved.