13:30 〜 15:30
▲ [13p-P5-43] Electrical and Mechanical Characteristics of Nanocrystalline Graphene Nano-Electro-Mechanical Switches
キーワード：Graphene, Nano Electro-Mechanical Switch, Finite Element Method (FEM) Simulation
Exceptional mechanical and electrical properties make graphene as a promising candidate for the Nano-Electro-Mechanical (NEM) Systems [1]. Moreover, three-terminal graphene NEM switch (Fig. 1 (a)) is expected to achieve an abrupt switching with a subthreshold slope less than 60 mV/dec. In the present work, we present the comprehensive three-dimensional finite-element-method (FEM) analysis of the double-clamped graphene beam NEM switch in order to analysis the pull-in and pull-out characteristics as well as the mechanical reliability. Structural dimensions of the doubly-clamped nanocrystalline graphene beam NEM switch are adapted from our previous experimental work [2].
The static electrical and mechanical characteristics of NEM switch are conducted by FEM based CAD tool IntelliSuite. In order to carry out the FEM simulation of the experimental device, we consider a graphene beam of length L, width W, and thickness t with a top metal electrode. The schematic representation of the device is shown in Fig. 1 (a). For FEM simulation, we have considered NEM switches with three different dimensions based on our experimental work: which are (1) NEM switch A of length (L) 1.5 µm, (2) NEM switch B of length (L) 1µm and (3) NEM switch C of length (L) 0.8µm. For all the NEM switches, width (W) and thickness (t) were set be 0.5 µm and 9 nm. The airgap was set to be 75 nm, 50 nm and 45 nm respectively for NEM A, B and C. The pull-in and pull-out characteristics of NEM switches are shown in Fig. 1 (c). Pull-in voltages of the NEM switch A, B, and C are 8.6 V, 13.2 V, and 20.8 V, respectively, which are consistent with our experimental results. The von Mises stress of the NEM switches was studied in order to analyze the mechanical reliability. The von Mises stress profile is shown in Fig. 1 (d) for the double-clamped graphene beams along their length. The von Mises stress reaches the maximum value towards the fixed end of the beam. The NEM switch C has the maximum von Mises stress of 6.2 GPa. When the length of the graphene beam is increased to 1 µm and 1.5 µm, the von Mises stress decreases to 3.8 GPa and 2.3 GPa, respectively. Further, we have analyzed the impact of applied electric fields on the double-clamped graphene beam. The electric field distribution between the fixed electrode and the doubly-clamped graphene is shown in Fig. 1 (e). Detailed discussion on the scaling of structural dimensions as well as the contact force analysis of doubly-clamped graphene NEM switch will be presented in the conference.
The static electrical and mechanical characteristics of NEM switch are conducted by FEM based CAD tool IntelliSuite. In order to carry out the FEM simulation of the experimental device, we consider a graphene beam of length L, width W, and thickness t with a top metal electrode. The schematic representation of the device is shown in Fig. 1 (a). For FEM simulation, we have considered NEM switches with three different dimensions based on our experimental work: which are (1) NEM switch A of length (L) 1.5 µm, (2) NEM switch B of length (L) 1µm and (3) NEM switch C of length (L) 0.8µm. For all the NEM switches, width (W) and thickness (t) were set be 0.5 µm and 9 nm. The airgap was set to be 75 nm, 50 nm and 45 nm respectively for NEM A, B and C. The pull-in and pull-out characteristics of NEM switches are shown in Fig. 1 (c). Pull-in voltages of the NEM switch A, B, and C are 8.6 V, 13.2 V, and 20.8 V, respectively, which are consistent with our experimental results. The von Mises stress of the NEM switches was studied in order to analyze the mechanical reliability. The von Mises stress profile is shown in Fig. 1 (d) for the double-clamped graphene beams along their length. The von Mises stress reaches the maximum value towards the fixed end of the beam. The NEM switch C has the maximum von Mises stress of 6.2 GPa. When the length of the graphene beam is increased to 1 µm and 1.5 µm, the von Mises stress decreases to 3.8 GPa and 2.3 GPa, respectively. Further, we have analyzed the impact of applied electric fields on the double-clamped graphene beam. The electric field distribution between the fixed electrode and the doubly-clamped graphene is shown in Fig. 1 (e). Detailed discussion on the scaling of structural dimensions as well as the contact force analysis of doubly-clamped graphene NEM switch will be presented in the conference.