Abstract
Cathode polarization potential during the electrodeposition of Cu from acid sulfate bath was studied by using cubic fibrous structure of Cu (100) substrate and the morphology of Cu electrodeposit was analyzed by the microscopic method as well as electron diffraction method.
By the addition of thiourea to the acid sulfate bath, it was found that the equilibrium potential of Cu electrode was displaced in the positive direction and cathode potential was constant in current density of 0.2-10mA/cm2.
It was confirmed that the morphology of crystal growth from acid Cu sulfate bath was varied with current density; i.e., pyramidal in 1mA/cm2, cubic layer in 10mA/cm2; and layer and block type in 30mA/cm2.
The concentration of thiourea had remarkable effects on the crystal morphology of Cu deposits in the change of size of crystal growth and pyramidal growth extended in [110] direction were varied with the concentration.
By the studies of electron diffraction of Cu deposits it was revealed that the preferred orientation (200) was found in the deposits from lower concentration of thiourea and lower current density. However, no preferred orientation was observed in the deposits from higher concentration of thiourea and higher current density.
