Porous Silicon Oxide Layer Formation by the Electrochemical Treatment of a Porous Silicon Layer

Abstract

A porous silicon layer (PSL) with pores of 40-200A diam was electrochemically treated at cathodic potentials in an aqueous KC1 solution. The treatment gave rise to the increase in proportion of silicon oxides. The surface had a porous structure of 0.5-2 t~m diam after the electrochemical treatment. A comparison study using He-Ne laser irradiation of the PSL was done that showed no distinct effects in the cathodic reaction rate compared with the electrochemical method. A surface-type humidity sensor was fabricated using the electrochemically treated silicon and found to be sensitive to changes in humidity over a wide range.

Silicon Porosification: State of the Art

“…110,[476][477][478] Many oxidation methods exist, such as aging in ambient, 479 exposure to water vapor, [480][481][482] anodic oxidation in a non-fluoride electrolyte, 142,179,[483][484][485] 479 and thermal oxidation in wet and dry O 2 fluxes, 189,381,[488][489][490][491] including rapid thermal oxidation. 477 A data review regarding a wide range of oxidation treatments (e.g., thermal treatments, electrochemical and chemical oxidation, pthotochemical oxidation, etc.)…”

Thermal Properties of Porous Silicon

“…For example, Aggarwal et al (2014) have shown that PSi samples oxidized under O 2 atmosphere had excellent stable surface and no degradation observed even after one year. Many oxidation methods exist, such as aging in ambient (Salonen et al 1997a), exposure to water vapor (Ogata et al 1995;Salonen et al 1997b;Ogata et al 2000), anodic oxidation in a nonfluoride electrolyte (Yamana et al 1990;Guerrero-Lemus et al 1999;Mulloni and Pavesi 2000;Kochergin and Foell 2006;Sakly et al 2006), chemical oxidation using HNO 3 (Leisenberger et al 1997), O 3 , H 2 O 2 (Frotscher et al 1996), vapor of pyridine (Mattei et al 2000), water solution of KNO 3 and alcohol (Salonen et al 1997a), and thermal oxidation in wet and dry O 2 fluxes (Unagami 1980;Maccagnani et al 1998;Kim et al 2001;Pap et al 2004Pap et al , 2005, including rapid thermal oxidation (Gelloz et al 2005). A data-review regarding a wide range of oxidation treatments (e.g., thermal treatments, electrochemical and chemical oxidation, photochemical oxidation, etc.)…”

Microstructure of Porous Silicon Thin Films

“…The School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245 Porous silicon has potential applications in the microelectronics industry. It has been investigated as an electroluminescent source 1 , as a sensing device in chemical sensors 2 and as an antireflective coating for solar cells. 3 ' 4 The low efficiency of the solar cells is enhanced by the antireflective coating that porous silicon provides, while the cost of fabrication of the cells is decreased.…”