Fabrication and characteristics of highly [Formula: see text]-oriented nanotwinned Au films

Fine grained and nanotwinned Au has many excellent properties and is widely used in electronic devices. We have fabricated [Formula: see text] preferred-oriented Au thin films by DC plating at 5 mA/cm². Microstructure analysis of the films show a unique fine grain structure with a twin formation. Hardness tests performed on electroplated [Formula: see text] Au films show a hardness 47% greater than random and untwinned Au. We then achieved direct bonding between two Au [Formula: see text] surfaces operating at 200 °C for an hour in a vacuum oven. The highly-oriented [Formula: see text] nanotwinned Au films could be an ideal material in many gold products.