Experimental evidence and modeling of two types of electron traps in Al2O3 for nonvolatile memory applications

L. SAMBUCO SALOMONE; J. LIPOVETZKY; S. H. CARBONETTO, M. A. GARCÍA INZA, E. G. REDIN; CAMPABADAL, F; A. FAIGON

JOURNAL OF APPLIED PHYSICS

AMER INST PHYSICS

Lugar: New York; Año: 2013 vol. 113 p. 74501 - 74508

0021-8979

Al2O3-based dielectrics are currently considered as promising materials to use in nonvolatile memories. The electron trap density in this material is much higher than in conventional SiO2, being their characteristics critical for the application. Conventional capacitance-voltage (C-V) techniques were used to study the main effects of the electron traps on the electrical characteristics of MOS capacitors with atomic layer deposited Al2O3 as insulating layer. More detailed information about the trapping kinetics was obtained through the study of the constant capacitance voltage transient. Two different types of traps were found. One is responsible for the instabilities observed in C-V measurements, the other has characteristic trapping times three orders longer. A physical model is presented to explain the observed trapping kinetics exhibiting good agreement between experiments and simulations. The energy levels of the studied traps were determined at 2.2 and 2.6 eV below the Al2O3 conduction band, with densities of 2.9 × 10E18cm−3 and 1.6 × 10E18−3, respectively.