Top-Down Fabrication of Silicon Nanowires in Ultra-deep Trenches

One-Dimensional (1D) nanostructures have gained a considerable attention in the field of semiconductor technology for the past several decades. With the help of rapid development in the process technology, it becomes possible to scale these nanostructures down, leading to higher performance devices.Even though there are some techniques which use bottom-up approach, the resulted structures suffer from the alignment and manipulation (pick and place) issues making a reliable integration even more difficult to achieve due to interfacing problems. In order to eliminate assembly issues, the limits of the conventional micro/nano-fabrication processes should be addressed and further studied. In addition, the use of single-crystal silicon in conventional micro/nano-fabrication processes gives the advantage of improved mechanical performance thanks to the lack of impurities and crystallographic defects as compared to their bottom-up counterparts.In this study, we exploit the approach of the well-known micromachining process called SCREAM (Single Crystal Reactive Etching and Metallization). Si NW is patterned on the silicon wafer by using e-beam lithography. Conventional reactive ion etching is then used to both suspend the patterned nanowire along with etching whole silicon surface, which will form the rest of the microscale device.