Electro-oxidation of p-silicon in fluoride-containing electrolyte: a physical model for the regime of negative differential resistance

Abstract

When Si is anodically oxidized in a fluoride containing electrolyte, an oxide layer is grown. Simultaneously, the layer is etched by the fluoride containing electrolyte. The resulting stationary state exhibits a negative slope of the current-voltage characteristics in a certain range of applied voltage. We propose a physical model that reproduces this negative slope. In particular, our model assumes that the oxide layer consists of both partially and fully oxidized Si and that the etch rate depends on the effective degree of oxidation. Finally, we show that our simulations are in good agreement with measurements of the current-voltage characteristics, the oxide layer thickness, the dissolution valence, and the impedance spectra of the electrochemical system.

Bichaoticity induced by inherent birhythmicity during the oscillatory electrodissolution of silicon

“…Its shape results from the competition between the electrochemical oxidation of the Si electrode to silicon oxide and the chemical etching of the oxide. The CV can be roughly divided in three regions: (i) the electropolishing branch below about 2 V where the current density increases strongly and the chemical etching of Si oxide is faster than its electrochemical oxidation 20,21 , (ii) the region of negative differential resistance (NDR) between about 2 V and 3-4 V where a so called 'wet', non-stoichiometric SiO x layer builds up on the electrode surface 22 , and (iii) the plateau region above 3 to 4 V where the oxide layer consists dominantly of stoichiometric SiO 2 . It is in region (iii) where oscillations are observed.…”

Two-Dimensionally Grown Periodic Pores Formed by Anodization of p-Type Silicon in Concentrated NH4F Aqueous Solution: A Platform for Maskless Patterning of Metals by Electrodeposition

“…Here, unlike previous related studies, we use p -Si to examine the electrochemical behavior carefully without any effect of illumination. The electrochemistry of Si during anodization has been investigated for more than 50 years; however, most of the previous related studies were either conducted using acidic solutions containing an F – ion , (e.g., HF solutions) or in basic (or sometimes neutral) solutions not containing an F – ion , (e.g., KOH solutions). The electrolytic solution used in the present study is neutral with an extremely high concentration of F – ions, differentiating our conditions from those used in previous studies.…”

Negative resistance amplifier circuit using GaAsFET modelled single MESFET

“…The concept of negative differential resistance (NDR) is mostly applied to produce oscillation in wireless communication systems at a desired frequency [10,11]. NDR is often employed in logic and memory circuits [12][13][14].…”