The electrical characteristics of nonvolatile memory, which consists of an asymmetrical ZrO2/SiO2 (ZO) modified tunnel barrier, a high-k HfO2 trapping layer and an Al2O3 blocking layer, were investigated for the application of a tunnel barrier engineered nonvolatile memory at low process temperatures. The efficiency of the ZO modified tunnel barrier on the charge trap flash (CTF) memory cell was compared to a conventional single SiO2 tunnel barrier. The ZO tunnel barrier revealed field sensitivity larger than the single SiO2 tunnel barrier. The programming and erasing speeds as well as the retention and endurance characteristics of CTF memory were largely enhanced. Moreover, the forming gas annealing process in 2% diluted H-2/N-2 ambient improved the charging trapping property and tunneling sensitivity of the ZO modified tunnel barrier. (C) 2011 Elsevier B.V. All rights reserved.