Narrow Results

The temperature-dependent resistivity measurements of our Ag–Ni–Si silicide films with 51–343 nm thicknesses are studied as a function of temperature and film thickness over the temperature range of 100–900 K. The most striking behavior is that the variation of the resistivity of the Ag–Ni–Si silicide films with temperature exhibits an unusual temperature-dependent behavior with respect to those of the transition and untransition metals. Our measurements show that the total resistivity of the Ag–Ni– Si silicide films increases linearly with temperature up to a T_m temperature at which resistivity reaches a maximum thereafter T_m decreases rapidly and finally to zero at ~850 K. T_m temperature is found to decrease with decreasing film thickness. We have shown that in the temperature range of 100-T_m K, electron–phonon resistivity and grain boundary resistivity components responsible for the total resistivity increase. But the grain boundary scattering is dominant mechanism for the resistivity increase in our Ag–Ni–Si silicide films.

The aim of our investigation is focused on studying the effect of dopant dose loss during annealing treatments on heavily doped surface layers, obtained by recoil implantation of antimony in silicon. We are interested particularly by the increase of sheet resistance consequently to the shallow junctions obtained at the surface of substrate and the contribution of the dopant dose loss phenomenon following the high concentration of impurities at the surface. In this work, we report some quantitative data concerning the dopant loss at the surface of silicon implanted and its dependence with annealing treatments. Electrical measurements associated with Rutherford backscattering (RBS) technical analysis showed interesting values of sheet resistance compared with classical ion implantation and despite dopant dose loss phenomenon.

The resistance and noise of films prepared with poor contacts are dominated by the contact interface and for perfect contacts holds that resistance and noise stem from outside the contact interface region. The proposed test pattern to study the different contributions uses one mask. It permits two- and four-point measurements enabling the detection of a weak contribution from outside the contact interface on top of a strong interface contribution. The resistance and noise for poor and perfect contacts are calculated between pairs of circular top electrodes of equal diameters 2r at distances L with L/2r = 10. The dependences of resistance and noise on the contact diameter are quite different for perfect and poor contacts.

1/f noise of films taken from literature are compared in the noise figure of merit K = C_us [cm²]/R_sh[Ω]. K is the ratio of 1/f noise normalized for bias, frequency and unit surface to sheet resistance. Materials can be classified based on K-values. Very high K-values point to inhomogeneous electric fields on a microscopic scale (percolation conduction). The contact interface 1/f noise and specific contact resistance are characterized by C_ust [cm²] and ρ_ct [Ω cm²]. Reviews of K for films and C_ust for interfaces show that 1/f noise is a more sensitive tool than merely the resistance parameters R_sh and ρ_ct.

Electrochemical deposition of cobalt nanoparticles was used to modify carrier transport properties of single-layered CVD graphene at the SiO₂-on-Si substrate. The structure of graphene with cobalt nanoparticles was analyzed by Raman spectroscopy and scanning electron microscopy. The effect of the deposited cobalt nanoparticles on the sheet resistance of graphene was studied in the temperature range of 4–300K.

A simple method for direct deposition of single-walled carbon nanotube (SWNT) networks on flexible substrates at room temperature is reported. Deposition of thin films was carried out using a two-zone tube furnace where the nucleation and growth of SWNTs occur in vapor phase in the hot zone and condense onto substrates in the cold zone. Raman spectroscopy and scanning electron microscopy reveal individual, uniformly distributed SWNTs over large areas (several cm²). The coverage density of the SWNTs on flexible substrates can be controlled by the location of the substrates within the cold zone. The opto-electronic properties of the thin films indicated that they can be transparent and conducting with sheet resistances ranging from 4 to 21 kΩ/sq at corresponding transparencies of 51 to 87%, respectively.

Nanocrystalline ruthenium (Ru)-doped ZnO thin films on sapphire substrate was prepared using sol–gel method by spin coating technique. The structural and I-V characteristics of Ru doped ZnO thin films were studied from the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) analysis and Raman spectroscopy. X-ray diffraction (XRD) results revealed that the deposited films belonged to hexagonal wurtzite structure with c-axis orientation. It is also confirmed from the Raman spectra. Enhancement of longitudinal optical (LO) phonon is observed by the strong electron–phonon interaction. An observed increment in sheet resistance with increase in dopant percentage of Ru (1–2mol%) in ZnO films was found and better I-V characteristic behavior was observed at 1mol% of Ru-doped ZnO thin films. Trap limited current flow inside the material was calculated from the log I versus log V plot in the higher voltage region.