Structure and stability studies on W, WSi, WSiN/GaAs systems by XRD

Abstract

The microstructural properties of tungsten, tungsten silicide and tungsten silicide nitride layers on GaAs were studied by thin film x-ray diffraction and correlated with deposition parameters, target composition and residual contamination during deposition. The x-ray diffractograms were used as 'fingerprints' for the existing phases in such contact layer/III-V semiconductor systems. It was found that in the as-deposited case of sputtered tungsten and WSi x the β-W phase can coexist, whereas in the case of reactively sputtered WSi x N y no other phases were found. After a series of rapid thermal annealing treatments diffractograms were measured showing W and/or W 5 Si 3 as dominating phases. The recrystallization temperatures of WSi x N y are found to be near 850 • C and 50 K higher than for the optimum WSi 0.45 . In contrast to WSiN, the recrystallization behaviour of WSi is strongly dependent on composition and contamination.

Preparation and characterization of ZnO nanoparticles coated by chitosan-linoleic acid; fungal growth and biofilm assay

“…As shown in Figure 3, the result showed characteristic peaks of ZnO crystalline structure observed in 100, 002, 101, 102, 110 and 103 (2θ) region. The results are in agreement with published reports and confi rmed the high purity of ZnO nanoparticles obtained (17).…”

AlGaN/GaN HFETs with New Ohmic and Schottky Contacts for Thermal Stability up to 400 °C

“…1, upper part, shows typical WSiN based ohmic source and drain contacts of samples B to D. Due to the properties of the WSiN sputter deposition process [9] the inner metal layers are entirely covered by WSiN which suppresses the roughening of the underlying contact metallization during rapid thermal annealing. It has to be taken into account that the WSiN barrier layer needs to be thicker than the underlying contact metallization.…”

Fabrication of near- or mid-infrared wire-grid polarizers with WSi wires

“…The sputtering or electron beam evaporation are usually used for the fabrication of WSi layers [18,19]. To attain an efficient polarization function, the wire material must have a large extinction coefficient κ, i.e., the imaginary part of the complex refractive index (n−jκ), must be large enough (κ » 1) to yield a high absorbance.…”