Electronic states at silicide-silicon interfaces

Abstract

A capacitance-spectroscopy technique based on accurate phase detection has been developed to measure the unoccupied states at silicide-silicon contacts. For Pd and Ni silicides, a dispersed group of states was found to exist in the Si band gap with its peak at a level 0.63-0.65 eV above the valence-band edge. Siiicide formation alters their density and distribution to reflect the changes in the structural perfection and barrier height. Observations on the epitaxial NiSi 2 -Si(lll) interfaces reveal that the characteristics of these states are controlled by the degree of structural perfection of the interface instead of the specific epitaxy. This seems to be the first correlation of the structural and electronic properties of a silicide-silicon interface.

Investigation of negative dielectric constant in Au/1 % graphene (GP) doped-Ca1.9Pr0.1Co4Ox/n-Si structures at forward biases using impedance spectroscopy analysis

“…The contrary to low frequencies, at high frequencies the charges at traps do not follow ac signal therefore do not yield any C ex and G ex /x to the C m and G m /x values. Such a peak behavior in the C-V and G/x-V plots in the depletion region has been ascribed to the D it by Ho et al [36], but according to Werner et al [37] the reason of the excess capacitance or anomalous peak can also be explained in the terms of minority carrier injection. In addition, Chattopadhyay et al [38] has theoretically shown that the peak value of C at forward biases varies with both R s and D it .…”

“…9 The variation of ac conductivity as a function of voltage for various frequencies J Mater Sci: Mater Electron surface exponentially and thus produces further spacecharge polarization, it leads to a rapid increase in the real and imaginary parts of dielectric constant and thus to a change in tand. The charges at traps also contribute to the polarization, but this contribution can be ignored at significantly high frequencies (f C 0.5 MHz) [36][37][38].…”

"Modeling memristive biosensors"

“…It is demonstrated in Fig.6 that the two current minima are clearly separated and a voltage gap appears in the semi-logarithmic current to voltage characteristics as due to the presence of the capacitors now introduced giving successful fitting with the experimental data. According to the literature concerning measurements of the junction capacitance [18]- [21] values for the space charge capacitance are referred to belong in the range beginning of pF [18], [19] and reaching the values of nF [20], [21]. Furthermore, it is mentioned that the excess capacitance is a result of the combination in parallel of the space charge capacitance characterizing the diode and of the diffusion capacitances due to the minority carriers' injection.…”

Computational Study on the Electrical Behavior of Silicon Nanowire Memristive Biosensors

“…Accumulating evidence from several works concerning relevant measurements [35]- [38] refers values for capacitances appearing in the junction area and refer to the space charge capacitance belonging in the range beginning of pF [35], [36] and reaching the values of nF [37], [38]. According to literature, the excess capacitance is a result of the combination in parallel of the space charge capacitance characterizing the diode and of the diffusion capacitances due to the minority carriers' injection.…”

“…Measurements of the junction capacitance is a very useful technique, giving information on Schottky barrier heights, dopant profiles, as well as the presence of traps and defects inside the semiconductor and at the interface [37].…”