Carrier Transport In Silicon Research Articles

Effect of Trap-Assisted Tunneling on Carrier Transport in Silicon Oxide/Polycrystalline Silicon

Effect of Trap-Assisted Tunneling on Carrier Transport in Silicon Oxide/Polycrystalline Silicon

Minority Carrier Injection in High-Barrier Si-Schottky Diodes

In this paper, we investigate the presence of minority carriers and their role in charge carrier transport in silicon (Si) Schottky diodes with a high potential barrier. Using TCAD simulations along with an analytical model, we show that an inversion charge is induced at the metal–semiconductor (MS) interface in a high-barrier Schottky diode which imparts bipolar-type current characteristics to otherwise a unipolar Schottky diode, even at low-injection operation. In such a high-barrier diode, minority diffusion also becomes important along with the majority carrier thermionic emission and therefore cannot be neglected, unlike in a conventional Schottky diode. The presence of minority carriers at low injection in a high-barrier Si Schottky diode has been experimentally verified via a prior-reported two-diode electrical test method, reverse recovery measurements, and by measuring infrared electroluminescence. It is also shown, via TCAD simulations, that the diffusion component becomes more pronounced in case of a reduced Gummel number and at elevated temperatures.

Dual-gate operation and carrier transport in SiGe p–n junction nanowires

We investigate carrier transport in silicon–germanium nanowires with an axial p–n junction doping profile by fabricating these wires into transistors that feature separate top gates over each doping segment. By independently biasing each gate, carrier concentrations in the n- and p-side of the wire can be modulated. For these devices, which were fabricated with nickel source–drain electrical contacts, holes are the dominant charge carrier, with more favorable hole injection occurring on the p-side contact. Channel current exhibits greater sensitivity to the n-side gate, and in the reverse biased source–drain configuration, current is limited by the nickel/n-side Schottky contact.

Electrical properties of silicon under nonuniform stress

We present a detailed analysis of the electronic carrier transport in silicon when subject to a nonuniform stress distribution. Such a distribution gives rise to two independent current components which can be viewed in terms of carrier generation-recombination. One component arises as a result of the nonuniform stress induced position dependent density of states, and the other due to stress induced shifts in the band edges. The various parameters and coefficients describing these phenomena are presented.

Non-homogeneous electrical transport through silicon-on-sapphire thin films: Evidence of the internal stress influence

The non-homogeneous electrical parameters of carrier transport in silicon on sapphire (SOS) films are investigated through galvanomagnetic experiments using “MOS-Hall” thin (0.65 μm) SOS devices with low n-type dopings ( n 0 ⋍ 10 15 to 10 16 cm −3 ). Capacitance-voltage (C-V), Hall and magnetoresistance measurements are performed on the gate-controlled depleted or “active” layers of the film. Experimental results and theoretical calculations show that longitudinal magnetoresistance (LMR) measurements yield the accurate determination of anisotropy and carrier drift mobility. On the contrary, it is underlined that the (previous) characterization methods, exclusively based on C-V or Hall experiments could produce inconsistent and misleading results in SOS. This is partly due to the fact that the usual 6 valley conduction band model used for bulk silicon is no longer valid in thin SOS films, for which the high stress at Si-sapphire interface requires the adoption of a 4 valley model throughout the film; this implies a high anisotropy for carrier mobility and explains why, in SOS films, the Hall mobility is 40% lower than the drift mobility, and the LMR is higher than the transverse magnetoresistance. C-V, Hall and LMR measurements then give fully consistent results allowing one to describe the variation of the carrier scattering mechanisms across the film and to determine the exact profiles for carrier mobilities and concentration as well as for the anisotropy coefficient.