Investigation of Electrochemical Oxidation Behaviors and Mechanism of Single-Crystal Silicon (100) Wafer under Potentiostatic Mode

Abstract

Electrochemical oxidation (ECO) has been used widely to oxidize single crystal Si wafers. Aiming at optimizing the ECO assisted machining methods, the oxidation behaviors of single- crystal silicon (100) wafer under potentiostatic mode are experimentally investigated. It is shown that the Si wafer can be electrochemically oxidized and the oxidized film thickness reaches to 239.6 nanometers in 20 min. The hardness of the oxidized surface is reduced by more than 50 percent of the original surface. The results indicate that the oxide thickness and the hardness can be controlled by changing the voltage. Based on the experimental findings, a hypothesis on the ECO mechanism under potentiostatic mode was proposed to explain the fluctuations of current density under specific applied voltage. The occurrence of the multiple peaks in the current density curve during the oxidation process is due to the formation of discharge channels, which was initiated from the defects at the interface between the oxide bottom and the substrate. This breaks the electrical isolation and leads to the discontinuous growth of the electrochemical oxide layer. The present work contributes to the fundamental understanding of the ECO behaviors for the single-crystal Si (100) wafer under potentiostatic mode.

A New Wire Electrode for Improving the Machining Characteristics of High-Volume Fraction SiCp/Al Composite in WEDM

“…Table 6 and Figure 7 show the acquired energy dispersive spectroscopy (EDS) analysis results of workpiece surfaces in Figure 6. As can be concluded from Table 6 and Figure 7, both the oxidation and element transfer effects occurred when processing the SiCp/Al composite in WEDM [55][56][57][58]. It can be found that oxygen atoms generally take more account of the workpiece surface processed by BWE than those processed by ZCSMWE by enforcing the same processing parameters.…”

Wafer‐Scale Electroactive Nanoporous Silicon: Large and Fully Reversible Electrochemo‐Mechanical Actuation in Aqueous Electrolytes

“…In particular, it is irreversible under the thereby employed electrochemical conditions. Moreover, we did not apply higher voltages, as the resulting formation of thick oxide layers (beyond 10 nm) [ 48,51 ] would have resulted in a complete oxidation of the pore walls and thus in a nonconductive porous layer. Hence, a capacitive charging of the nanopores would have been impossible.…”

Effect of surfactant and etching time on p-type porous silicon formation through potentiostatic anodization

“…While most previous investigations used galvanostatic anodization of Si (where the current density remains constant), the application of the potentiostatic oxidation of silicon is still an open subject in the field [8,[14][15][16][17]. Actually, notwithstanding the undoubted importance of electrical potential in controlling the properties of PSi, electrochemical oxidation of silicon has mainly been carried galvanostatically, as opposed to potentiostatically, because of the difficulty of working with reference electrodes in HF solutions [14].…”

“…Scaling up the process to industry standard of 200 mm diameter wafers does not foresee any fabrication challenges. Aside from the well-established galvanostatic anodization, potentiostatic anodization is gaining attention in structuring micro-/nanomaterials lately[17,19,[28][29][30][31], and this work can be used as a block in building advanced technologies.…”