Many materials systems are currently under consideration as potential replacements for SiO2 as the gate dielectric material for sub-0.1 μm complementary metal–oxide–semiconductor (CMOS) technology. A systematic consideration of the required properties of gate dielectrics indicates that the key guidelines for selecting an alternative gate dielectric are (a) permittivity, band gap, and band alignment to silicon, (b) thermodynamic stability, (c) film morphology, (d) interface quality, (e) compatibility with the current or expected materials to be used in processing for CMOS devices, (f) process compatibility, and (g) reliability. Many dielectrics appear favorable in some of these areas, but very few materials are promising with respect to all of these guidelines. A review of current work and literature in the area of alternate gate dielectrics is given. Based on reported results and fundamental considerations, the pseudobinary materials systems offer large flexibility and show the most promise toward success...

/pdf/high-k-gate-dielectrics-current-status-and-materials-zjvba0c4u8.pdf

High-κ gate dielectrics: Current status and materials properties considerations

Hafnium and zirconium silicate (HfSixOy and ZrSixOy, respectively) gate dielectric films with metal contents ranging from ∼3 to 30 at. % Hf, or 2 to 27 at. % Zr (±1 at. % for Hf and Zr, respectively, within a given film), have been investigated, and films with ∼2–8 at. % Hf or Zr exhibit excellent electrical properties and high thermal stability in direct contact with Si. Capacitance–voltage measurements show an equivalent oxide thickness tox of about 18 A (21 A) for a 50 A HfSixOy (50 A ZrSixOy) film deposited directly on a Si substrate. Current–voltage measurements show for the same films a leakage current of less than 2×10−6 A/cm2 at 1.0 V bias. Hysteresis in these films is measured to be less than 10 mV, the breakdown field is measured to be EBD∼10 MV/cm, and the midgap interface state density is estimated to be Dit∼1–5×1011 cm−2 eV−1. Au electrodes produce excellent electrical properties, while Al electrodes produce very good electrical results, but also react with the silicates, creating a lower e l...

Hafnium and zirconium silicates for advanced gate dielectrics

Dielectric properties of ultrathin hafnium oxide reoxidized with rapid thermal annealing (RTA) have been investigated. Capacitance equivalent oxide thickness (CET) of 45 A hafnium oxide was scaled down to ∼10 A with a leakage current less than 3×10−2 A/cm2 at −1.5 V (i.e., ∼2 V below VFB). Leakage current increase due to crystallization was not observed even after 900 °C rapid thermal annealing (RTA), but CET did increase after high temperature RTA due to the interfacial layer growth and possible silicate formation in the HfO2 film.

Thermal stability and electrical characteristics of ultrathin hafnium oxide gate dielectric reoxidized with rapid thermal annealing

Atomic layer deposition (ALD) of smooth and highly conformal films of hafnium and zirconium oxides was studied using six metal alkylamide precursors for hafnium and zirconium. Water was used as an oxygen source during these experiments. As deposited, these films exhibited a smooth surface with a measured roughness equivalent to that of the substrate on which they were deposited. These films also exhibited a very high degree of conformality:  100% step coverage on holes with aspect ratios greater than 35. The films were completely uniform in thickness and composition over the length of the deposition reactor. The films were free of detectable impurities and had the expected (2:1) oxygen-to-metal ratio. Films were deposited at substrate temperatures from 50 to 500 °C from precursors that were vaporized at temperatures from 40 to 140 °C. The precursors were found to be highly reactive with hydroxylated surfaces. Their vapor pressures were measured over a wide temperature range. Deposition reactor design and ...

Atomic Layer Deposition of Hafnium and Zirconium Oxides Using Metal Amide Precursors

Highly efficient semiconducting TiO2 photoelectrodes prepared by aerosol pyrolysis

Chemical vapor deposition and characterization of HfO2 films from organo-hafnium compounds

Thin films of metal oxides on silicon by chemical vapor deposition with organometallic compounds. I

The chemical vapour deposition and characterization of ZrO2 films from organometallic compounds

The Characteristics of Growth of Films of Zirconium and Hafnium Oxides (ZrO2, HfO2) by Thermal Decomposition of Zirconium and Hafnium β‐Diketonate Complexes in the Presence and Absence of Oxygen

THE CHARACTERISTICS OF GROWTH OF FILMS OF ZIRCONIUM AND HAFNIUM OXIDES (ZRO2, HFO2) BY THERMAL DECOMPOSITION OF ZIRCONIUM AND HAFNIUM β-DIKETONATE COMPLEXES IN THE PRESENCE AND ABSENCE OF OXYGEN

S. Patai

Papers

Chemical vapor deposition and characterization of HfO2 films from organo-hafnium compounds

Thin films of metal oxides on silicon by chemical vapor deposition with organometallic compounds. I

The chemical vapour deposition and characterization of ZrO2 films from organometallic compounds

The Characteristics of Growth of Films of Zirconium and Hafnium Oxides (ZrO2, HfO2) by Thermal Decomposition of Zirconium and Hafnium β‐Diketonate Complexes in the Presence and Absence of Oxygen

THE CHARACTERISTICS OF GROWTH OF FILMS OF ZIRCONIUM AND HAFNIUM OXIDES (ZRO2, HFO2) BY THERMAL DECOMPOSITION OF ZIRCONIUM AND HAFNIUM β-DIKETONATE COMPLEXES IN THE PRESENCE AND ABSENCE OF OXYGEN