The typical flow of device modeling and characterization consists of four critical steps, with each integral to the quality and reliability of the final models:
Data measurement and analysis: This first stage involves gathering measured data from various semiconductor devices across different wafers and temperatures. The focus here is on precision and efficiency.
Model extraction: Model extraction complexity varies with the technology and specific device model. Device modeling software is instrumental at this stage, offering advanced graphics, links to circuit simulators, optimizers, and manual tuners to extract parameters. For RF modeling, custom programming might be necessary to account for parasitic effects in S-parameters.
Model validation: This step is fundamental to ensure the reliability of the modeling libraries by running simulations over extended bias, geometry, and frequency conditions. Tools like Device Modeling MQA (Model Quality Assurance) can automate much of this process, simplifying the testing and helping to identify and report any issues efficiently.
Integration into process design kits (PDKs): The final step involves integrating device modeling libraries into PDKs. A critical but challenging aspect of this phase is PDK validation, which involves extensive re-verification of sample designs whenever there's a new release of a simulator software version or an update to a design kit. The goal is to ensure that the PDKs remain accurate and consistent across different updates.