Collapse behavior and forces of multistack nanolines

Abstract

Two types of multistack nanolines (MNLs), Si-substrate (Si)/siliconoxynitride (SiON)/amorphous Si (a-Si)/SiO2 and Si/SiO2/polycrystalline Si (poly-Si)/SiO2 were used to measure the collapse force and to investigate their collapse behavior by an atomic force microscope (AFM). The Si/SiON/a-Si/SiO2 MNL showed a larger length of fragment in the collapse patterns at a smaller collapse force. The Si/SiO2/poly-Si/SiO2 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/SiO2 and Si/SiO2/poly-Si/SiO2 MNLs. Once an AFM tip touches an Si/SiON/a-Si/SiO2 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/SiO2/poly-Si/SiO2, however, was broken at two ends simultaneously after the delamination occurred at the Si/SiO2/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.