Memory characteristics of Al2O3/La2O3/SiO2 multi-layer structures for charge trap flash devices

Seung Yong Cha, Hyo June Kim, Doo Jin Choi

Research output: Contribution to journalArticlepeer-review


The Charge Trap Flash (CTF) memory device is a replacement candidate for the NAND Flash device. In this study, Pt/Al2O3/La2O3/SiO2/Si multilayer structures with lanthanum oxide charge trap layers were fabricated for nonvolatile memory device applications. Aluminum oxide films were used as blocking oxides for low power consumption in program/erase operations and reduced charge transports through blocking oxide layers. The thicknesses of SiO2 were from 30 Å to 50 Å. From the C-V measurement, the largest memory window of 1.3V was obtained in the 40 Å tunnel oxide specimen, and the 50 Å tunnel oxide specimen showed the smallest memory window. In the cycling test for reliability, the 30 Å tunnel oxide sample showed an abrupt memory window reduction due to a high electric field of 9~10MV/cm through the tunnel oxide while the other samples showed less than a 10% loss of memory window for 104 cycles of program/erase operation. The I-V measurement data of the capacitor structures indicated leakage current values in the order of 10-4 A/cm2 at 1V. These values are small enough to be used in non-volatile memory devices, and the sample with tunnel oxide formed at 850°C showed superior memory characteristics compared to the sample with 750°C tunnel oxide due to higher concentration of trap sites at the interface region originating from the rough interface.

Original languageEnglish
Pages (from-to)462-467
Number of pages6
JournalKorean Journal of Materials Research
Issue number9
Publication statusPublished - 2009

All Science Journal Classification (ASJC) codes

  • Materials Science(all)


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