Electrodeposition of CoWP film II. Effect of electrolyte concentration

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.

Tribological and corrosive characteristics of electrochemical coatings based on cobalt and iron superalloys

“…1i) and so does their roughness under certain conditions with electrolyte temperature increasing to 60°C (i c = 5 A/dm 2 ) ( Table 2). The similar effect associated with increase in phosphorus content of the alloy is noted in [34].…”

“…Increasing phosphorus content of Co-W-P alloy [34] decreases the sizes of crystallites. Figure 3 shows that the nanohardness of ternary alloys increases with loading.…”

Characterisation of electrodeposited Co–W–P amorphous coatings on carbon steel

“…Recently, it has been reported that electrodeposition method has some advantages over electroless deposition such as lower processing temperature, better control over the deposition technique and thus, a wide range of compositions [12][13][14][15]. In the present work, Co-W-P coatings have been made on plain carbon steel by the electrodeposition method and their microstructures, hardness and corrosion protective properties have been studied.…”

“…Co-W-P thin films can be fabricated by both electroless [8][9][10][11] and electrochemical deposition methods [12][13][14][15]. Recently, it has been reported that electrodeposition method has some advantages over electroless deposition such as lower processing temperature, better control over the deposition technique and thus, a wide range of compositions [12][13][14][15].…”

Development of an alkali-metal-free bath for electroless deposition of Co-W-P capping layers for copper interconnections

“…Co-W-P thin films can be deposited by both electroless [10][11][12] and electrochemical [17][18][19][20] deposition methods. The electroless plating, however, is widely used to deposit the metallic capping/barrier layers because it is a very simple and inexpensive method, does not require much instrumentations and offers highly selective and conformal deposition [5,12,15].…”