Low-temperature magnetron sputter-deposition, hardness, and electrical resistivity of amorphous and crystalline alumina thin films

Aluminum oxide films were grown by reactive magnetron sputtering. In order to maintain a stable deposition process and high deposition rate, a pulsed direct current bias was applied to the aluminum target and the substrate. A n external solenoid was used to form a magnetic trap between the target and the substrate. The influence of substrate temperature, substrate bias, and the magnetic trap on film growth and properties was studied by different s urface and thin-film analysis techniques and electrical measurements. Norma lly, amorphous alumina films were produced. However, under optimum process conditions, crystalline alumina films can be obtained at temperatures as lo w as 250 degrees C, with a hardness similar to 20 GPa and excellent electri cal insulating properties. (C) 2000 American Vacuum Society, [S0734-2101(00 )04605-4].