A stoichiometric, uniform, and amorphous hafnium oxide thin film is deposited by an atomic layer deposition process. The as-deposited hafnium oxide films showed superior electrical properties compared to zirconium oxides, including a dielectric constant of 23, a flatband voltage shift of +0.3 V, a hysteresis of 25 mV, an interfacial trap density of 1.8×1011 cm−2 eV−1, and a leakage current density several orders of magnitude lower than SiO2 at an equivalent oxide thickness of 9.3 Å, suitable for metal–oxide–semiconductor device applications. The thermal stability of hafnium oxide on silicon was determined to be better than that of zirconium oxide. Post-deposition annealing in oxygen and ammonia further improved the thermal stability of HfO2 to 1000 and 1100 °C, respectively.

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Articles you may be interested inDegradation mechanisms of electron mobility in metal-oxide-semiconductor field-effect transistors with LaAlO 3 gate dielectricHf O 2 -based InP n -channel metal-oxide-semiconductor field-effect transistors and metal-oxide-semiconductor capacitors using a germanium interfacial passivation layer Appl. Phys. Lett. 93, 102906 (2008); 10.1063/1.2961119 Physical model for frequency-dependent dynamic charge trapping in metal-oxide-semiconductor field effect transistors with Hf O 2 gate dielectric Appl. Phys. Lett. 86, 093510 (2005); 10.1063/1.1874312 Low-frequency noise characteristics of HfSiON gate-dielectric metal-oxide-semiconductor-field-effect transistors Appl. Phys. Lett. 86, 082102 (2005); 10.1063/1.1866507Rapid thermal chemical vapor deposition of zirconium oxide for metal-oxide-semiconductor field effect transistor application J.

Articles you may be interested inBand alignment of HfO2/Al0.25Ga0.75N determined by x-ray photoelectron spectroscopy: Effect of SiH4 surface treatment Appl. Phys. Lett.X-ray photoelectron spectroscopy (XPS) combined with first principles simulations are used to investigate the band alignments of HfO 2 on silicon. Our theoretical calculations predict dangling bond states originating from the partial occupancy of Hf d orbitals at a stoichiometric HfO 2 /Si interface. Our band structure calculations predict that hydrogen passivation of Hf atoms at the interface as well as increased oxygen concentration at the interface remove the dangling bond states effectively. A HfSiO 4 / Si interface also has no dangling bond states. Theoretically calculated valence band offsets of HfO 2 / Si interface ranged from 2.69 to 3.04 eV and the conduction band offsets ranged from 1.54 to 1.89 eV, and they are a function of the interface coordination numbers. For the HfSiO 4 / Si interface, the calculated valence and conduction band offsets are 2.69 eV and 2.19 eV, respectively. Experimentally measured band offsets by XPS yield a valence band offset of 3.10 eV and a conduction band offset of 1.48 eV for a HfO 2 / Si interface, in very good agreement with theoretical results. These results suggest that HfO 2 and HfSiO 4 provide sufficient tunneling barriers for electrons and holes, making them suitable candidates as alternative gate dielectrics.

X-ray photoelectron spectroscopy combined with first-principles simulations are used to determine the band alignments of ZrO2 thin films on silicon. Theoretical band offsets were calculated by simulating the ZrO2/Si interface by means of plane-wave pseudopotential calculations. Experimental band offsets were determined by measuring the core-level to valence-band maximum binding energy differences. Excellent agreement was obtained between the theoretical (3.5–3.9 eV) and experimental (3.65 eV) valence band offsets. Both theoretical and experimental analyses predict the conduction band offset to be ∼0.6–1.0 eV which indicates the intrinsic limitation of ZrO2 to be considered as a viable alternative gate dielectric.