TY - JOUR
T1 - Low-damage fabrication of high aspect nanocolumns by using neutral beams and ferritin-iron-core mask
AU - Kubota, Tomohiro
AU - Baba, Tomohiro
AU - Saito, Suguru
AU - Yamasaki, Satoshi
AU - Kumagai, Shinya
AU - Matsui, Takuo
AU - Uraoka, Yukiharu
AU - Fuyuki, Takashi
AU - Yamashita, Ichiro
AU - Samukawa, Seiji
N1 - Funding Information:
The authors thank Rikako Tsukamoto and Kazuaki Nishio of Matsushita Electric Industrial, Co., Ltd. for preparing the salt-free ferritin molecules. They also thank Norikazu Mizuochi of National Institute of Advanced Industrial Science and Technology for valuable comments on the ESR measurements. This study is supported by Leading Project of Ministry of Education, Culture, Sports, Science and Technology, Japan.
PY - 2007
Y1 - 2007
N2 - A silicon-nanocolumn structure was fabricated by using neutral beams and a ferritin-iron-core mask. The etching process was observed by scanning electron microscope and x-ray photoelectron spectroscopy (XPS), which revealed that the iron core can be used as an etching mask for more than 30 min of etching. Extrapolation of the XPS results shows that it is possible to fabricate nanocolumns about 180 nm high. The diameter at the top of the nanocolumns was about 7 nm after etching for 5 min or longer, while it was about 12 nm after etching for 2.5 min. It is thus concluded that the current etching condition is applicable for fabricating nanocolumns about 20-180 nm high and 170-nm -high nanocolumn was fabricated. Densely distributed nanocolumns with a narrow gap of 5.5 nm between them could be etched successfully. To demonstrate that nanocolumns can be used for devices and circuits, a regularly arranged nanocolumn array was fabricated successfully. Etching damage was investigated by transmission electron microscope (TEM) and electron-spin resonance (ESR). The TEM observation revealed that the interior and subsurface of the nanocolumns kept a single-crystal structure completely, and no crystalline defects were observed. A small amount of Pb centers were found by ESR measurement and attributed to silicon dangling bonds at the nanocolumn sidewalls. The dangling-bond density was not increased by neutral-beam etching and stayed low (i.e., 2.7× 1011 cm-2) after etching. Damage-free etching was thus achieved by neutral beam. This result may be attributed to the absence of UV photons in the neutral beam. Such a sub- 10-nm process with an arranged pattern and low etching damage has great potential in regard to the development of future nanometer-scale devices.
AB - A silicon-nanocolumn structure was fabricated by using neutral beams and a ferritin-iron-core mask. The etching process was observed by scanning electron microscope and x-ray photoelectron spectroscopy (XPS), which revealed that the iron core can be used as an etching mask for more than 30 min of etching. Extrapolation of the XPS results shows that it is possible to fabricate nanocolumns about 180 nm high. The diameter at the top of the nanocolumns was about 7 nm after etching for 5 min or longer, while it was about 12 nm after etching for 2.5 min. It is thus concluded that the current etching condition is applicable for fabricating nanocolumns about 20-180 nm high and 170-nm -high nanocolumn was fabricated. Densely distributed nanocolumns with a narrow gap of 5.5 nm between them could be etched successfully. To demonstrate that nanocolumns can be used for devices and circuits, a regularly arranged nanocolumn array was fabricated successfully. Etching damage was investigated by transmission electron microscope (TEM) and electron-spin resonance (ESR). The TEM observation revealed that the interior and subsurface of the nanocolumns kept a single-crystal structure completely, and no crystalline defects were observed. A small amount of Pb centers were found by ESR measurement and attributed to silicon dangling bonds at the nanocolumn sidewalls. The dangling-bond density was not increased by neutral-beam etching and stayed low (i.e., 2.7× 1011 cm-2) after etching. Damage-free etching was thus achieved by neutral beam. This result may be attributed to the absence of UV photons in the neutral beam. Such a sub- 10-nm process with an arranged pattern and low etching damage has great potential in regard to the development of future nanometer-scale devices.
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U2 - 10.1116/1.2732734
DO - 10.1116/1.2732734
M3 - Article
AN - SCOPUS:34249864119
VL - 25
SP - 760
EP - 766
JO - Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
JF - Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
SN - 1071-1023
IS - 3
ER -