Abstract
A gate stack structure with a thin ZnO layer between an oxidized Si(100) surface and an alloyed hafnium and lanthanum oxide (HfO2-La 2O3) layer was prepared by plasma enhanced atomic layer deposition at ∼175 °C. High resolution electron microscopy indicated an amorphous structure of the deposited layers. The electronic properties were characterized with x-ray and ultraviolet photoemission spectroscopy. A significant amount of excess oxygen was observed in the as-deposited ZnO and (HfO2-La2O3) layers. A helium plasma postdeposition treatment can partially remove the excess oxygen in both layers. The band alignment of this structure was established for an n-type Si substrate. A valence band offset of 1.5 ± 0.1 eV was measured between a thin ZnO layer and a SiO2 layer. The valence band offset between HfO 2-La2O3 (11 HfO2 and 89 La 2O3) and ZnO was almost negligible. The band relationship developed from these results demonstrates confinement of electrons in the ZnO film as a channel layer for thin film transistors.
Original language | English (US) |
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Article number | 051807 |
Journal | Journal of Vacuum Science and Technology B:Nanotechnology and Microelectronics |
Volume | 30 |
Issue number | 5 |
DOIs | |
State | Published - Sep 2012 |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Instrumentation
- Process Chemistry and Technology
- Surfaces, Coatings and Films
- Electrical and Electronic Engineering
- Materials Chemistry