Effects Of Current Density, Etching Time And Hydrofluoric Acid Concentration On The Formation And Morphology Of Highly Doped N-Type Porous Silicon

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dc.contributor.authorYaakob, Suriani Haji
dc.date.accessioned2018-08-16T07:33:13Z
dc.date.available2018-08-16T07:33:13Z
dc.date.issued2011-07
dc.description.abstractHighly doped n-type porous silicons (PS) were prepared via electrochemical etching. The effect of current density (50 – 300 mA cm-2), etching time (30 – 300 s) and HF concentration (9.2 – 49.0% (v/v)) on the morphology, pore diameter, porosity, surface roughness and electrical properties of the PS were studied. These properties were characterized by Scanning Electron Microscopy (SEM), gravimetric method, Atomic Force Microscopy (AFM) and Current-Voltage (I-V) characteristics. The increment in current density has changed the morphology of the PS from interconnected network to columnar with side branching. However, with the increase in the etching time and HF concentration, this disappeared to give smooth side wall pores. The pore diameter increased with increase in current density, but decreased with HF concentration and remained consistent at 19.0 ± 2.8 nm with the etching time. The porosity of PS was increased with increase in current density and etching time, but decreased with the HF concentration. An optimum value of the surface roughness at 150 mA cm-2 of current density and 180 s of etching time was obtained in all ranges of parameters studied. However, a decreasing trend was observed with the increase in HF concentration. The electrical properties of PS also decreased with the increase in porosity in all studied conditions. The electro-polishing was found to occur at current density > 300 mA cm-2 and etching time > 300 s. Similar observations on the PS formed at low HF concentration of 9.2% (v/v) and current density of 150 mA cm-2 as well as that formed in 19.6% (v/v) HF at 300 mA cm-2 were obtained. The obtained PS was also employed as a host for metallic copper (Cu) deposition by immersion plating. The SEM results showed that the morphology of Cu particles changed from cubes to close-pack spheres upon addition of 1:1 (v/v) methyl ethyl ketone (MEK) into the Cu salt (0.001 M) solution prior to immersion process. This improved the Cu particles coverage onto the PS surface compared to immersion process using Cu salt solely. The size of Cu particles was controllable by varying the immersion time.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/6337
dc.language.isoenen_US
dc.publisherUniversiti Sains Malaysiaen_US
dc.subjectHighly doped n-type porous siliconsen_US
dc.subjectprepared via electrochemical etchingen_US
dc.titleEffects Of Current Density, Etching Time And Hydrofluoric Acid Concentration On The Formation And Morphology Of Highly Doped N-Type Porous Siliconen_US
dc.typeThesisen_US
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