Pulse electrodeposition of Ni-W alloy for trench filling in microelectromechanical systems

• Published in: Journal of nanoscience and nanotechnology Vol. 8; no. 10; p. 5321
• Main Authors: Jung, Hayong, Hong, Chan, Kil, Junghee, Kim, Jutae, Kim, Bonghan, Tak, Yongsug
• Format: Journal Article
• Language: English
• Published: United States 01.10.2008
• ISSN: 1533-4880
• DOI: 10.1166/jnn.2008.1189

The effect of pulse current (PC) on Ni-W alloy electrodeposition was investigated to fill the trenches with aspect ratio 1:2 for MEMS applications. Rapid deposition of top side in trench produced a void in electrodeposits with direct current (DC). Morphology of Ni-W electrodeposition inside trench was strongly influenced by the applied current density and the current off-time (t(off)). Enhanced filling phenomena were observed with increasing current off-time because of decreasing concentration gradient between top and bottom in trench. The complete Ni-W filling of trench was achieved with a current density of 200 mA/cm2 and a current on- and off-time of 100 ms and 300 ms, respectively. Amorphous structure was revealed in both DC and PC electrodeposits and the concentration of W in Ni-W electrodeposits for complete filling of trench was about 24% in atomic ratio.