Collapse behavior and forces of multistack nanolines.

Two types of multistack nanolines (MNLs), Si-substrate (Si)/siliconoxynitride (SiON)/amorphous Si (a-Si)/ SiO(2) and Si/ SiO(2) /polycrystalline Si (poly-Si)/ SiO(2) were used to measure the collapse force and to investigate their collapse behavior by an atomic force microscope (AFM). The Si/SiON/a-Si/ SiO(2) MNL showed a larger length of fragment in the collapse patterns at a smaller collapse force. The Si/ SiO(2) /poly-Si/ SiO(2) MNL, however, demonstrated a smaller length of fragment at a higher applied collapse force. The collapse forces increased by the square of the linewidth in both Si/SiON/a-Si/ SiO(2) and Si/SiO(2) /poly-Si/ SiO(2) MNLs. Once an AFM tip touches an Si/SiON/a-Si/ SiO(2) line, which is a softer MNL, it was delaminated first at the Si/SiON interface. One end of the delaminated line was first broken and then the other end was bent until it was broken. A harder MNL, Si/ SiO(2) /poly-Si/ SiO(2), however, was broken at two ends simultaneously after the delamination occurred at the Si/ SiO(2) /poly-Si interface. The different collapse behaviors were attributed to the magnitude of adhesion forces at the stack material interfaces and the mechanical strength of MNLs.