| AVS 65th International Symposium & Exhibition | |
| Thin Films Division | Monday Sessions |
| Session TF+EM+MI+PS-MoA |
| Session: | Thin Films for Advanced Memory Applications and Magnetics |
| Presenter: | Lee Woo Chul, Center for Electronic Materials, Korea Institute of Science and Technology, Korea |
| Authors: | L. Woo Chul, Center for Electronic Materials, Korea Institute of Science and Technology, Korea C. Cheol Jin, Center for Electronic Materials, Korea Institute of Science and Technology, Korea K. Sangtae, Center for Electronic Materials, Korea Institute of Science and Technology, Korea L. Eric S., Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), South Korea Y. Jung Hwan, Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), South Korea H. Cheol Seong, Department of Materials Science and Engineering, and Inter-University Semiconductor Research Center, College of Engineering, Seoul National University, South Korea B. Christopher W., Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), South Korea K. Seong Keun, Center for Electronic Materials, Korea Institute of Science and Technology, Korea |
| Correspondent: | Click to Email |
BeO has a very large band gap (10.6 eV), which is even larger than that of representative large band gap materials; SiO2 (~9 eV) and Al2O3 (~8 eV). BeO thin films reveal high quality of the interface with Si and semiconductors, showing a possibility as a gate dielectric. Furthermore, rocksalt BeO was recently predicted to have a very high dielectric constant (~ 275) and a very large band gap (10.6 eV). However, the fascinating dielectric properties have not been experimentally realized yet because of the instabilty of the rocksalt BeO. Nowdays, atomic layer deposition (ALD) is a common technique for film growth in a semiconductor industry. The ALD process of the BeO thin films is necessary to be developed to implement BeO in the semicoductor industry. Herein, the growth characteristics and properties of BeO thin films grown by ALD are investigated. We demonstrated that ALD chemistries between dimethylberyllium (DMB) and two different oxygen sources, H2O and O3, are governed by different reaction mechanisms, resulting in different film properties.
BeO thin films were grown in a traveling-wave type reactor by ALD with DMB and different oxygen sources, such as H2O and O3, in the temperature range of 150 to 300 oC. Although H2O-ALD and O3-ALD of BeO all showed self-saturation behavior, the growth behavior and film properties are strongly dependant on the oxygen sources. With increasing growth temperatures, the growth per cycle (GPC) of H2O-ALD of BeO decreases, while that of O3-ALD of BeO is almost constant. The properties of the BeO films grown in H2O-ALD are nearly temperature-independent, whereas the BeO films grown in O3-ALD at low temperatures (< 200 oC) reveal high impurity concentrations and a low film density. These cause lowering of the band gap and dielectric constant of the BeO films grown by O3-ALD at low temperatures. These findings demonstrate that the O3-ALD process requires relatively more thermal energy than H2O-ALD does, to produce high-quality BeO thin films.