Loading...

Simulation and Analysis of of NEM Relays for Low Power VLSI Applications

Mousavi, Mohammad Reza | 2023

95 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 56529 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Sarvari, Reza
  7. Abstract:
  8. Over the past five decades, the proliferation of electronic devices and the advent of Internet of Things (IoT) technology have ushered in a profound revolution in integrated circuit technology. In contemporary electronics, digital integrated circuits rely predominantly on CMOS transistors. Among the notable limitations associated with CMOS transistors are their non-zero off-state current and limited sub-threshold slope. In response to these limitations, researchers have ventured into a burgeoning field known as "Beyond CMOS," exploring technologies like Tunnel Junctions, Carbon Nanotube FETs, and more. Additionally, alternative approaches that blend electronic and mechanical principles in minuscule dimensions have emerged, known as micro/nano electromechanical switches. Initially, through a comprehensive examination of various electromechanical switch types in terms of actuation, it was determined that electrostatic switches exhibited superior characteristics across multiple aspects. Hence, we opt for this relay type. After familiarizing ourselves with the structure of this relay variant, we will select one of the latest proposed electromechanical relay structures employing electrostatic actuation. Subsequently, we will conduct simulation and optimization using COMSOL software. The primary structure has the pull-In voltage (V_PI) of 110 mV, the switching time (τ_ON) of 6.5 ns, and the total electrical energy of 0.55 fJ. To enhance the performance of these switches, we modified the original structure. During the static pull-in analysis, we initially reduced the air gap (g_0), resulting in a lowered pull-in voltage of 69.3 mV. Subsequently, we increased the length of the beams, fine-tuning the pull-in voltage to a more optimized 87 mV. Following that, through a combination of decreasing the air gap and adjusting the spring constant (K_eff), we successfully lowered the pull-in voltage to 58.3 mV. Also, by increasing the area of the moving part (A_ACT), the PI voltage reached 68 mV. In the subsequent analysis (switching time analysis), we achieved optimization by decreasing the spring constant (K_eff), resulting in a total electrical energy consumption of 0.53 fJ. Additionally, reducing the air gap size (g_0) further decreased the electrical energy to 0.31 fJ and reduced the switching time to 3.8 nS. Next, to optimize this structure as much as possible, we used the body and applied bias voltage to it. In the first analysis, by applying a body voltage of -10 mV, we obtained a PI voltage of 50 mV. After that, by applying the voltage of -11 mV, -12 mV and -13 mV, we were able to optimize the PI voltage and obtain the values of 44 mV, 40 mV and 33 mV, respectively. Also, in the second analysis, by applying body voltage of -80 mV and -90 mV, we obtained the switching time of 3.4 ns and 3.3 ns
  9. Keywords:
  10. Delay ; Energy Consumption ; Low Power Very Large Scale Integration (VLSI) ; Pull-In Voltage ; Electromechanical Switches ; Switching Time

 Digital Object List

 Bookmark

...see more