| AVS 54th International Symposium | |
| Electronic Materials and Processing | Thursday Sessions |
| Session EM-ThA |
| Session: | High-K/High Mobility Substrates and Power Electronics |
| Presenter: | J. Zhang, Imperial College London, UK |
| Authors: | S.Y. Chiam, Imperial College London, UK W.K. Chim, National University of Singapore A.C. Huan, Institute of Materials Research and Engineering, Singapore J. Zhang, Imperial College London, UK S.J. Wang, Institute of Materials Research and Engineering, Singapore J.S. Pan, Institute of Materials Research and Engineering, Singapore S.G. Turner, Imperial College London, UK |
| Correspondent: | Click to Email |
Band alignment is an important property for oxides-semiconductor lineup especially for MOS devices. Band offsets for many oxides-semiconductor has and can be predicted by charge neutrality level (CNL) model (gap states model). This model however is based on an essentially "bulk" phenomenon of gap states dipoles. There have been, however, differences in the measured valence band offsets (VBO) and conduction band offsets (CBO) of oxides (especially rare-earth oxides) and the predicted offsets from the CNL model. In this work, we present the experimental data for rf-sputtered Y2O3 on Si, Ge, strain-Si, strain-SiGe and relaxed SiGe. The virtual substrates were grown by GSMBE. Some of these substrates expect differences (based on various sources, investigating changes in conduction and valence band) in the valence and conduction band of less then 0.1eV. However, the VBO and CBO between the oxide and these substrates amounts often to >0.5eV. In addition, we have pre-sputtered a thin mono-layer of Y metal before deposition of the Y2O3 (in-situ). This reduces the valence band offset for the films on all the substrates. This can be explained by changes in either interface structure and/or chemical nature at the interface (dipoles). Our work shows the importance of the nature at the interface in determining the offsets between an oxide and semiconductor.