Chemical interface analysis of as grown HfO2 ultrathin films on SiO2

Abstract

The quality of the interface between a HfO2 high-k gate dielectric and the Si substrate directly influences its electrical properties. The chemical composition of the interfacial region of HfO2 deposited on a SiO2∕Si(100) substrate by pulsed liquid injection metal organic chemical vapor deposition at 430 and 550°C was investigated by medium energy ion scattering, angular resolved x-ray photoemission spectroscopy analysis, and high resolution transmission electron microscopy. It is shown that the HfO2∕SiO2 interface is abrupt with low roughness and no silicate. The interface roughness with SiO2 is found to be close to that generally measured in silicon technology (silicon oxide above silicon substrates) [E. A. Irene, Solid-State Electron., 45, 1207 (2001)]. The analysis of the experimental results indicates that the deposition technique does not lead to the formation of an extended silicate layer at the HfO2∕SiO2 interface.

Interfacial and structural properties of sputtered HfO2 layers

“…Since this shift is equal to that of neither Si 4+ nor S 3+ , and being very close to that of Si 4+ , this can be inferred as the oxide containing Hf-O-Si, i.e., Hf silicate ͑HfSi x O y ͒. [26][27][28] The existence of this thick layer was also supported from the FTIR absorption spectrum ͑Fig. 2͒.…”

“…The chemical shift for Si 3+ , i.e., the difference in the binding energy of the component and that of elemental Si, is generally obtained at about 2.48-2.65 eV far from the position of elemental Si, i.e., 99.3 eV. 26 This chemical shift was, however, obtained ϳ3.4-3.7 eV for deeper layers of the oxide. Since this shift is equal to that of neither Si 4+ nor S 3+ , and being very close to that of Si 4+ , this can be inferred as the oxide containing Hf-O-Si, i.e., Hf silicate ͑HfSi x O y ͒.…”

π‐σ‐Phosphonic Acid Organic Monolayer/Sol–Gel Hafnium Oxide Hybrid Dielectrics for Low‐Voltage Organic Transistors

“…[20] Indeed, HfO 2 -based high-k dielectrics have emerged as leading candidates to replace SiO 2 for scaling below the 65 nm node in advanced metal-oxide-semiconductor applications. Typical processing routes for HfO 2 include atomic layer deposition, [21] chemical vapor deposition, [22] and physical vapor deposition. Although these techniques achieve highquality films with nanometer precision, they each have drawbacks and all require expensive high vacuum equipment.…”

Low-voltage organic field-effect transistors based on novel high-κ organometallic lanthanide complex for gate insulating materials

“…[7][8][9] The common high-κ dielectric is inorganic metal-oxides in general. [10][11][12][13][14][15][16] Up to now, it still is of great importance to develop novel high-κ materials as gate insulator, especially organic high-κ dielectric. Recently, it is reported that organometallic lanthanide complexes, a kind of neutral mononuclear molecule-based materials, have the merit of good thermal stability, high dielectric constants (high-κ), easy thin film formation by thermal evaporation method.…”