Electrical features of the metal-thin porous silicon-silicon structure

Abstract

This paper considers a theoretical model of the metal-tunnel interface layer-thin porous silicon-p-Si structure. A diffusion-drift equation at the appropriate boundary conditions is solved to clarify a mechanism of the carriers' transport. The voltage drop distribution along the structure is calculated by solving the equations under the condition of continuity of the vector of the electrostatic induction. The obtained analytical expressions allow one to analyse the contribution of the interface layer, porous silicon and surface electron states to the electrical behaviour of the structure. Some parameters of the model are defined from the comparison of experimental I-V and C-V characteristics with theoretical values for the Pd-porous silicon (60% of porosity)-p-Si structures having different thicknesses of porous silicon layers. The defined barrier height eφ0 ranged from 0.45 to 0.47 eV, the interface layer consisted of mainly the native oxide achieved up to 3.0 nm and did not depend on the time of Si electrochemical etching. The evidence that part of the voltage drops on the surface electron states is ensued by comparing the experimental high frequency C-V curves with steady-state I-V curves. Thickening of the porous silicon layer results in a shift in the energetic band of the surface electronic states.

Method for Determination of Characteristics of Sensors Based on Electroconducting Polymers

“…According to [3][4][5], the hydrogen sensing mechanism includes the adsorption and dissociation of hydrogen molecules in the Pd, the transport of hydrogen atoms across the catalytic metal film and the formation of dipoles at the metal-insulator interface. To explain the dependence of the I-V characteristics on hydrogen concentration we can apply the model of Schottky contact with the PS and SiO 2 interface layer [13]. Then the I-V characteristics can be given by I=I s [ exp (eU s /kT) -exp(-eU l /kT)], where U= U s +U l , U s and U l -parts of voltage drops on Si and PS, respectively, the dark saturation current I s is expressed via the barrier heights and the effective coefficient of transparency of PS interface.…”

The Mechanism of Metal-Assisted Etching of Silicon

“…Most of the reports available on gold, copper, palladium, indium, and titanium as contact metals to PSi are found rectifying (Han et al 1994;Jeske et al 1995;Simons et al 1995;Diligenti et al 1996;Ichinohe et al 1996;Angelescu and Kleps 1998;Matsumoto et al 1998;Skryshevsky et al 1998;Slobodchikov et al 1998Slobodchikov et al , 1999Lue et al 1999;Bhattacharya et al 2000;Vikulov et al 2000;Ghosh et al 2002a;Rabinal and Mulimani 2007;Gallach et al 2012). The metal alloys like Au-In, In-Sn, and so on showed rectifying behavior (Angelescu and Kleps 1998).…”

Basics of MIS-type gas sensors with thin nanoporous silicon

“…Both the diffusion and drift components of electrical current should be considered in the diffusion theory. The solving of diffusion-drift equation allows obtaining the expression for I-V characteristics [13]:…”