No abstract

No abstract

No abstract

No abstract

Electrochemical characterization of electrodeposition of CoWP films on copper substrate from a citrate electrolyte was carried out using voltammetry and chronoamperometry techniques. The voltammetry experiments revealed that codeposition of cobalt, tungsten, and phosphorus from an electrolyte containing cobalt sulfate, sodium tungstate, sodium hypophosphite, and tri-sodium citrate occurred via a nucleation process under mass-transfer control. The chronoamperometric study showed an instantaneous nucleation mechanism during electrocrystallization of CoWP on copper. Finally, a bath was developed from which CoWP thin films were deposited at room temperature on copper-coated silicon wafers. Surface analysis using X-ray photoelectron spectroscopy revealed that the films contained elemental cobalt, tungsten, phosphorus, hydroxide of cobalt, and oxides of cobalt and tungsten. Scanning electron microscopy and atomic force microscopy images showed that the films had typical spherical nodular structures with good uniformity and dense coverage.

No abstract

No abstract

CoWP films were electrodeposited on coppercoated silicon wafers from citrate electrolyte containing cobalt sulphate, sodium tungstate and sodium hypophosphite at room temperature potentiostatically. The effects of electrolyte concentration on thickness, composition and microstructure of the films were studied. It was observed that the deposition current density and thickness increased with increasing cobalt and hypophosphite ion concentrations, whereas an increase in tungstate ion concentration resulted in a decrease in current density and thickness. Films with larger variations of cobalt (from 64 to 83 at.%), tungsten (from 0.5 to 24 at.%) and phosphorus (from 6 to 21 at.%) were electrodeposited by controlling the concentrations of the electrolytes. X-ray diffraction studies suggested that films containing *20 at.% phosphorus were amorphous while films with lower phosphorus content were crystalline. SEM and AFM examinations showed that the size of crystallites and surface roughness were mainly dependent on the amount of phosphorus present in the films.