PREPARATION OF ULTRAFINE CU AND SNO2 PARTICLES BY DC-MAGNETRON SPUTTERING

Ultrafine particles of copper and SnO2 were prepared by particle nucleation and growth in the gas phase using d.c. magnetron sputtering. Particles of both materials exhibited octahedral habits, were crystalline with a narrow particle size distribution and were of high purity. This study verified the feasibility of producing ultrafine particles in the size range 15-60 nm for copper and 5-25 nm for SnO2 cassiterite. The principal process variables studied were gas pressure, power on the target and substrate temperature. This sputtering method for ultrafine particles is characterized by a higher gas pressure (200-1100 mTorr) and a higher power level (1-3 kW) compared with the conventional sputter deposition process for films, which involves operation at pressures in the range 0.1-10 mTorr.