Influence of 700 °C vacuum annealing on fracture behavior of micro/nanoscale focused ion beam fabricated silicon structures

Abstract

In this paper, we describe the influence of 700 °C vacuum annealing on strength and fracture behavior of micro- and nano-scale Si structures fabricated by focused ion beam (FIB). Si nanowires (NWs) made from silicon-on-nothing (SON) membrane are fabricated using FIB. Microscale Si specimens are fabricated by conventional micromachining technologies and FIB. These specimens are tensioned to failure using specially developed microelectromechanical systems (MEMS) device and thin-film tensile tester, respectively. The mean fracture strengths of the nano- and microscale specimens are 5.6 and 1.6 GPa, respectively, which decrease to 2.9 and 0.9 GPa after vacuum annealing at 700 °C for only 10 s. These strength values do not vary with increasing annealing time. Fracture origin and its behavior are discussed in the light of fracture surface and FIB damage layer observations.

Temperature Dependence on Tensile Mechanical Properties of Sintered Silver Film

“…In this study, we investigate the influence of test temperature on the mechanical characteristics of s-Ag ( p : 5%) and p-Ag thin films with 8–10 μm in thickness. The originally designed tensile tester [ 24 , 25 , 26 , 27 ] is used to characterize the stress–strain ( S-S ) behaviors of these films at temperatures ranging from RT to 150 °C. The fracture mechanism at each temperature is discussed in the light of fracture surface observation using a scanning electron microscope (SEM).…”

Mechanical Property Measurement of Micro/Nanoscale Materials for MEMS: A Review

“…The strength of Si MEMS structures formed by wet etching is typically higher than that by dry etching even if the specimen size is comparable. FIB processed Si structures include a damaged layer consisting of Ga ion included amorphous Si, which reduces its mechanical reliability [70][71][72][73][74]. Ina et al [72] compared mechanical characteristics of four types of Si nanowires, FIB milled nanowire, annealed FIB milled nanowire, FIB implanted amorphous nanowire, and conventional single crystal Si nanowire.…”

“…9. Microstructure of FIB-made Si nanowire before and after annealing in high vacuum [72][73][74] In the most case, the damaged layer started recrystallization at the interface to single crystal Si portion, as shown in Fig. 9, and it was changed to poly crystal, not single crystal.…”

“…Thermal process is used as a surface modification tool. By annealing Si wafer with dry-etched holes in vacuum, cavities can be formed inside the Si wafer [73,74]. The process might be used for hermetic packages for nanodevices.…”

“…The strength of Si MEMS structures formed by wet etching is typically higher than that by dry etching even if the specimen size is comparable. FIB processed Si structures include a damaged layer consisting of Ga ion included amorphous Si, which reduces its mechanical reliability [70–74]. Ina et al .…”