Immersion plating of copper on porous silicon in various solutions

The mechanism of immersion plating of copper on porous silicon is studied. Copper metal is deposited on the surface of porous silicon at a rest potent ial in aqueous solution. It is shown that presence of chloride ions in copp er sulfate solution inhibits the metal deposition, whereas the deposition i s possible in cuprous chloride solution even though the concentration of ch loride ions is high. nlc behavior is explained in terms of different comple xing states of copper ions in each solution. The cathodic reaction is accom panied by thr oxidation of silicon as the counter reaction. Immersion plati ng in nonaqueous organic solution shows that a trace of residual water affe cts the copper deposition, The difference between metal deposition on porou s silicon and a silicon wafer is also discussed.