The interfacial reactions and electrical characteristics of stack structures of La2O3 and Al2O3 were investigated as a function of the annealing temperature. In the case of Al 2O3/La2O3/Si (ALO structure), the La2O3 in contact with the Si substrate was readily transformed into La-silicate by the diffusion of Si atoms, while in the case of La2O3/Al2O3/Si (LAO structure), interfacial reactions between the Al2O3 layer and the Si substrate were suppressed. After an annealing treatment at 700° C, the Al 2O3 in the ALO structure can play an effective role in blocking the hydration of La2O3, resulting in an unchanged interfacial layer. However, the Al2O3 layer in the LAO structure was unable to suppress the diffusion of Si atoms into the La 2O3 film. When the annealing temperature reached 900°C, both structures showed a similar depth distribution with a high content of Si atoms diffused into the films. The change in the elemental distributions via the diffusion and reaction of Si atoms affected the electrical characteristics at the interface between ALO/LAO structure and Si substrate, specifically the trap charge density (Dit) and band gap (E g) values.
Bibliographical noteFunding Information:
This work was partly supported by a grant from the Joint Program for Samsung Electronics–Yonsei University and the IT R&D program of MKE/KEIT [10035320, Development of novel 3D stacked devices and core materials for next generation flash memory].
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Physics and Astronomy(all)