Fabrication and Phase-Transition Characteristic Investigation of Nanocrystalline VO2 Thin Film

In this paper, nanocrystalline VO2 thin film is fabricated by a kind method of two steps and its phase transition characteristics are investigated. The two-step method contains low-temperature reactive ion sputtering and post-annealing, and its process parameters determine the phase transition properties of fabricated VO2 thin film. With optimized process parameters, VO2 thin film with nanocrystalline structure can be successfully fabricated and has excellent phase transition performance for smart glass and optical switch.

High Mobility Nitrides

The highest mobility nitrides ever grown were indium nitride polycrystalline thin films. The original reactive ion sputtering unit used to produce those films is still in existence and has been substantially upgraded. In this paper we describe some of the parameters that are important for high purity indium nitride growth, while providing the most recent results for films grown with the upgraded system. A long lag time (greater than 100 hours of growth time) has been observed before obtaining stable material properties for a given set of growth conditions.

Photoemitters Based on Glass - ITO Structures

The sample was a silicon glass with conducting films (ITO) evaporated by reactive ion sputtering on its both sides. The internal electric field was created by applying a negative polarizing voltage Upol, to field electrode. The investigations were performed in the vacuum of the order 10−6 Pa. As a result of applying Upol and illumination, photoelectrons are released and enter electron multiplier. The electrons create voltage pulses in the multiplier which are recorded in the multichannel pulse amplitude analyzer. The amplitude spectra were measured for unilluminated samples and illuminated by a quartz lamp.Energy analysis of emitted electrons was performed by the retarding field method. Measurements of electrons energy in field induced emission showed that about 80% o electrons have energy up to 10 eV but some electrons of higher energy are also detected. The described effects can be modeled with support of the electron effects occurring during the intrinsic discharges in gases. Theoretical molecular dynamics simulations have shown that SnO4 tetrahedral interacting with SiO4 clusters of the glass substrate play central role in the observed nonlinear photoinduced changes.

PVD Ti-Si-N Films Process Development for Copper Interconnect Applications

ABSTRACTA process has been developed for the deposition of amorphous Ti-Si-N films using reactive ion sputtering of a TiSi target. The Ti-Si-N films have been extensively characterized over a wide range of process parameters. Resistivities of the films less than 300 μΩ-cm have been achieved. Stress measurements on Ti-Si-N films indicate that the film stress changes from tensile to compressive as the nitrogen composition is increased. Near-zero film stresses were achieved by choice of optimum nitrogen N2 flow. SIMS analysis of Cu diffusion through blanket PVD Ti-Si-N (300Å) after an anneal at 390°C/3 hour showed a near overlap of the Cu profile compared to the profile of an unannealed SiO2/PVD Ti-Si-N /Cu film stack, indicating that the Cu did not diffuse significantly through the barrier after anneal. Low contact resistance (0.8 Ω) and low (< 10−11 A) leakage were obtained using a dual inlaid structure with a 300 Å Ti-Si-N processed with optimized conditions. These results showed that Ti-Si-N could be used as a potential barrier for copper metallization.

In Situ Study of the Bonding of Impurities in Metal-Impurity-Metal Laminate Composites

The local structure of interface or near interface impurity elements has been observed by means of extended x-ray absorption fine structure spectroscopy (EXAFS). Multilayered samples were prepared using reactive ion sputtering, electron beam evaporation , and molecular beam deposition methods with vacuum conditions ranging from 10−5 to 10−9 Pa. The interface layers of titanium, gallium, and arsenic were deposited in partial to multiple atom layers alternating with 5 to 10 nm thick matrix layers of nickel, cobalt, or aluminum. Oxide phases, atoms in solution, and local ordering were identified. Ti oxides and silicon arsenide were used as standards for the EXAFS analysis. Auger electron spectroscopy complemented the EXAFS analysis.