Apr 6, 2009
Uninvited Au atoms modify device performance
The interface between a metal and a semiconductor plays a crucial role in determining device characteristics and is expected to have a pronounced effect on the performance of nanoscale devices. To learn more, scientists have performed transmission electron microscopy analysis in combination with electrical transport measurements.
Researchers from the Korea Research Institute of Chemical Technology (KRICT), Yonsei University, and National NanoFab Center (NNFC) have teamed up to investigate nanoscale interfaces. The Yonsei University group, led by Heon-Jin Choi has synthesized SiGe alloy nanowires with different compositions, and the KRICT team, together with scientists at Chonbuk National University, have built nanowire structures on a transparent membrane and characterized the electrical characteristics of the devices. The transmission electron microscopy analysis was performed at NNFC.
Si1–xGex alloy nanowire devices with Ni/Au or Ni contacts were built on a free-standing Si3N4 membrane for TEM analysis. Devices with Ni/Au contacts show reproducible resistance switching behavior after annealing, while devices with only Ni contacts did not show such a switching effect. TEM analysis revealed the presence of pronounced Au atoms at the interface between semiconducting alloy nanowire and metallic silicide (shown in the figure above). Although the exact mechanism behind the observed resistance switching is not clear yet, the authors believe that inter-diffused Au atoms can affect device performance greatly, and it may be possible to develop devices that take advantage of such a hysteresis effect.
About the author
The work was performed at KRICT. Eun-Kyoung Jeon is a PhD student studying Physics at Chonbuk National University, and Han-Kyu Seong is a PhD student at Yonsei University. TEM investigations were performed by Hyunsang Seo and Dr. Chi Won Ahn at NNFC. For other research activities ongoing in KRICT, please visit http://nbalink.krict.re.kr