This full 3D SAW filter model provides a complete picture of device performance. By simulating the device in full 3D a range of parasitic effects can be considered to avoid carrying undesirable performance into production.
The typical workflow for the design and development of MEMS devices is based on a mask layout design. It combines the 2D mask layout with the process flow to create 3D solid models of the MEMS devices. The layout-based discretized 3D models need to be converted into system models. Now, these high-fidelity MEMS 3D models can contain between 100,000 to 1,000,000 degrees of freedom to fully capture the effect of process flow on 3D geometry and its effect on device performance. FEA simulations of these models with legacy software can take a few days to run and sometimes it is not even possible to run these models. Given this a MEMS design engineer must rely on reduced-order or lumped model approximations, which do not truly capture the effect of etching, residual stresses and packaging effects. This makes the system design optimization of MEMS devices a big challenge to achieve the required performance.
At OnScale we have developed fast time domain multiphysics 3D finite-element (FE) solvers and seamlessly integrated them with cloud high performance computer (HPC) capabilities that address these constraints. MEMS design engineer can now import full 3D high-fidelity models of MEMS devices created in Mentor Graphics / SoftMEMS and run FEA simulations in OnScale to accurately understand the performance of these devices in less than few hours.
In this example we will show you how to run the model on the cloud and post-process the results using the OnScale Post Processor.
Model Description
The model comprises a pair of gold IDT electrodes on a piezoelectric substrate. These are terminated with a grating. The substrate can either be Lithium Tantalate (LiTaO3) or Lithium Niobate (LiNbO3). The model is set up to simulate a Y-cut, which can be rotated to the desired angle.
Download and Open the Model
Download: SAW Resonator SoftMEMS Import Model
OnScale input files have the file extension *.flxinp. To open the downloaded file:
- Open OnScale.
- Select Analyst mode.
- Click the menu button in the top-left of the application and select Open Project.
Preview Model
Preview Model is used to view both the geometry dimensions and the material assignment of a model to ensure that everything is correct. To preview a model, click Preview Model in the Home tab of the application ribbon. To close the preview, click Stop Preview.
Run Model on Cloud
To run the model on the cloud, click Run on Cloud in the Home tab of the application and follow these steps:
- Click Estimate.
- Set CPUs to 4.
- Click Run.
Download Results
- From the Home tab, click Storage.
- Click the refresh icon to refresh storage.
- Select the job name from the dropdown menu.
- Click Download and select Download All.
Choose a directory to download the results to. These results will be stored in the folder: active_SAW_Reson...-YYYYMMDD-HHMMSS\1 where YYYYMMDD-HHMMSS is the current date and time.
Switch to Post Processor
Post Processor is a suite of tools used to visualise and analyze output data generated from OnScale simulations. To switch to Post Processor, click the button in the top-right:
Analyze Results
To plot the velocity in Z, follow these steps:
- In File Explorer, navigate to the download directory and double-click the file active_SAW_Resonator_onscale_cut_angle_v1.flxhst to load it.
- In Results Manager, double-click zvel to plot the Z velocity in the model.
You can also calculate impedance/admittance on the electrodes by selecting the voltage or charge records from the Results Manager and clicking the impedance and admittance buttons found in the XY Tools section of the Home tab. Below is a plot of the impedance.
