Carbon doped oxide dielectrics comprised of Si, C, O, and H (SiCOH) have been prepared by plasma enhanced chemical vapor deposition (PECVD) from mixtures of tetramethylcyclotetrasiloxane (TMCTS) and an organic precursor. The films have been analyzed by determining their elemental composition and by Fourier transform infrared spectroscopy with deconvolution of the absorption peaks. The analysis has shown that PECVD of TMCTS produces a highly crosslinked networked SiCOH film. Dissociation of TMCTS appears to dominate the deposition chemistry as evidenced by the multitude of bonding environments and formation of linear chains and branches. Extensive crosslinking of TMCTS rings occurs through Si–Si, Si–CH2–Si, Si–O–Si, and Si–CH2–O–Si moieties. The films deposited from mixtures of TMCTS and organic precursor incorporate hydrocarbon fragments into the films. This incorporation occurs most probably through the reaction of the organic precursor and the Si–H bonds of TMCTS. Annealing the SiCOH films deposited from TMCTS and organic precursor results in a large loss of carbon and hydrogen from the films resulting from the fragmentation and loss of the incorporated organic component. The deconvolution of the Si–O–Si asymmetric stretching band of the annealed films shows the existence of a larger fraction of a cage structure and a correspondingly smaller fraction of a networked (highly crosslinked) structure in the SiCOH films deposited from mixtures of TMCTS with organic precursor relative to the films deposited from TMCTS only. The evolution of the volatile hydrocarbon fragments during annealing results in the formation of nanopores and subsequent reduction of the dielectric constants of the films to extreme low-k values.

The high dielectric constant of insulators currently investigated as alternatives to SiO2 in metal–oxide–semiconductor structures is due to their large ionic polarizability. This is usually accompanied by the presence of soft optical phonons. We show that the long-range dipole field associated with the interface excitations resulting from these modes and from their coupling with surface plasmons, while small in the case of SiO2, for most high-κ materials causes a reduction of the effective electron mobility in the inversion layer of the Si substrate. We study the dispersion of the interfacial coupled phonon-plasmon modes, their electron-scattering strength, and their effect on the electron mobility for Si-gate structures employing films of SiO2, Al2O3, AlN, ZrO2, HfO2, and ZrSiO4 for “SiO2-equivalent” thicknesses ranging from 5 to 0.5 nm.

The thermal stability, microstructure, and electrical properties of xZrO2⋅(100−x)SiO2 (ZSO) and xHfO2⋅(100−x)SiO2 (HSO) (x=15%, 25%, 50%, and 75%) binary oxides were evaluated to help assess their suitability as a replacement for silicon dioxide gate dielectrics in complementary metal–oxide–semiconductor transistors. The films were prepared by chemical solution deposition using a solution prepared from a mixture of zirconium, hafnium, and silicon butoxyethoxides dissolved in butoxyethanol. The films were spun onto SiOxNy coated Si wafers and furnace annealed at temperatures from 500 to 1200 °C in oxygen for 30–60 min. The microstructure and electrical properties of ZSO and HSO films were examined as a function of the Zr/Si and Hf/Si ratio and annealing temperature. The films were characterized by x-ray diffraction, mid- and far-Fourier transform infrared (FTIR), Rutherford backscattering spectroscopy, and Auger electron spectroscopy. At ZrO2 or HfO2 concentrations ⩾50%, phase separation and crystallization of tetragonal ZrO2 or HfO2 were observed at 800 °C. At ZrO2 or HfO2 concentrations ⩽ 25%, phase separation and crystallization of tetragonal ZrO2 or HfO2 were observed at 1000 °C. As the annealing temperature increased, a progressive change in microstructure was observed in the FTIR spectra. Additionally, the FTIR spectra suggest that HfO2 is far more disruptive of the silica network than ZrO2 even at HfO2 concentrations ⩽25%. The dielectric constants of the 25%, 50%, and 75% ZSO films were measured and were observed to be less than the linear combination of ZrO2 and SiO2 dielectric constants. The dielectric constant was also observed to increase with increasing ZrO2 content. The dielectric constant was also observed to be annealing temperature dependent with larger dielectric constants observed in nonphase separated films. The Clausius–Mossoti equation and a simple capacitor model for a phase separated system were observed to fit the data with the prediction that to achieve a dielectric constant larger than 10 doping concentrations of ZrO2 would have to be greater than 70%.

Impact of metal gates on remote phonon scattering in titanium nitride/hafnium dioxide -channel metal-oxidesemiconductor field effect transistors-low temperature electron mobility study

The AlGaInN quaternary alloy system is uniquely suited for numerous device applications because the bandgap can be varied from 1.9 to 6.2 eV by changing the alloy composition. Growth of epitaxial device-quality group III (Al, Ga, In) nitride films has been hindered by a lack of suitably lattice matched substrates, the large equilibrium dissociation pressure of N 2 from the nitrides at typical growth temperatures, and predeposition reactions in the commonly employed metal-organic chemical vapor (MOCVD) precursors. The most successful films have been grown at temperatures in excess of 900 °C by MOCVD. However, high growth temperatures may limit compatibility and incorporation of group III nitrides with existing fabrication technologies and devices. Attempts to lower deposition temperature include activated nitrogen sources and alternative precursors. This review will discuss improvement in film properties as a function of growth chemistry and will focus on MOCVD precursors used specifically for the growth of group III nitrides.