| AVS 56th International Symposium & Exhibition | |
| Electronic Materials and Processing | Tuesday Sessions |
| Session EM2-TuM |
| Session: | Complex and Multifunctional Oxides |
| Presenter: | B. Aguirre, University of Texas at El Paso |
| Authors: | B. Aguirre, University of Texas at El Paso R.S. Vemuri, University of Texas at El Paso D. Zubia, University of Texas at El Paso W. Jiang, Pacific Northwest National Laboratory M.H. Engelhard, Pacific Northwest National Laboratory V. Shutthanandan, Pacific Northwest National Laboratory C.V. Ramana, University of Texas at El Paso |
| Correspondent: | Click to Email |
Hafnium oxide (HfO2), which exhibits a very high dielectric constant (k) and large bandgap, is considered as a next-generation high-k material for application in complementary metal-oxide-semiconductor (CMOS) technology. However, growth of high-quality HfO2 layers on Si without the formation of interfacial compounds poses a significant challenging problem. The objective of the present work was to optimize the conditions to grow high-quality HfO2 nanolayered films on Si(100). In our work, HfO2 films were grown by RF sputtering of HfO2 ceramic target at various substrate temperatures (Ts= 30-500 oC) and studied their structure and electrical properties. Al/HfO2/Si capacitive structures were fabricated to obtain a metal-oxide-semiconductor (MOS) configuration to mimic the gate stack of CMOS technology and study the electrical properties. Grazing incidence x-ray diffraction (GIXRD) and X-ray photoelectron spectroscopy (XPS) measurements indicate that the effect of Ts is significant on the microstructure. HfO2 films grown at Ts<200 oC are amorphous. An amorphous-to-crystalline transition occurs at Ts=200 oC. Nanocrystalline HfO2 films crystallized in a monoclinic structure with a particle size ~20 nm. XPS measurements indicate the high chemical quality of HfO2 films grown at Ts=30-500 oC. The capacitance-voltage characteristics of the Al/HfO2/Si devices indicate that HfO2 films grown (or post-deposition annealed) at 400 oC exhibit the expected monoclinic-HfO2 characteristics. HfO2 films exhibit a direct correlation with the microstructure. The results obtained are presented and discussed in detail.