How to Obtain CMOS Technology Parameters and Design Fundamentals

When working with CMOS technology, it is essential to understand the various parameters involved in the design and manufacturing process. These parameters include those characterized by SPICE models and those provided by the semiconductor foundries that manufacture the silicon. This article will guide you through the process of obtaining these parameters and help you understand their importance in CMOS design.

Understanding SPICE and BSIM Models

If you are familiar with SPICE (Spiced), the BSIM (Bipolar-Silicon-Controlled Rectifier Model) models characterize approximately one hundred process parameters. BSIM models are widely used to simulate the behavior of MOS transistors and provide essential information for the design of CMOS circuits. These parameters are crucial for predicting the performance of the devices under different operating conditions.

Accessing Old Technology Parameters

For old technology parameters, you can find valuable resources on university professors' webpages. Depending on the tool being used (e.g., PSpice), you may be able to locate the necessary data readily. A recommended approach is to use Predictive Technology Models, such as those provided by the NC State University (NCSU) EDA Wiki. NCSU's models are both open and free for all students and researchers, making them valuable resources for academic and research purposes.

Through the NCSU EDA Wiki, you can access advanced models for various technologies, including 45nm and 23nm. These models provide detailed information on the behavior of CMOS transistors at these scales, which is crucial for advanced circuit design.

Foundry-Supplied CMOS Design Parameters

For the most accurate and up-to-date CMOS technology parameters, it is best to obtain them directly from the foundry that intends to manufacture your silicon. Foundries typically provide comprehensive documentation with detailed parameters and specifications for their processes. This documentation is vital for ensuring optimal performance and reliability of the final product.

The foundry parameters include:

Fabrication Process Parameters: These cover the various steps involved in the fabrication of CMOS devices, including lithography, etching, doping, and deposition processes. Electrical Parameters: Key electrical properties such as threshold voltage, subthreshold leakage, and transconductance. Performance Metrics: Information on power consumption, switching speed, and current-voltage characteristics. Process Variability: Data on the expected variability in device characteristics due to manufacturing processes.

By utilizing the foundry's parameters, you can refine your design to meet the specific requirements of the production process, ensuring successful implementation.

Conclusion

Obtaining CMOS technology parameters is a critical step in the design and manufacturing process. Whether you are using predictive models or directly consulting foundry documentation, it is essential to have accurate and reliable data to guide your design choices. SPICE models and foundry-supplied parameters are just two of the many resources available to aid in the CMOS design process. By leveraging these tools and resources, you can enhance the performance and reliability of your CMOS circuits.