A Scalable RFCMOS Noise Model

This paper presents the high-frequency (HF) noise modeling of an RF MOSFET for a 90-nm technology node. A brief discussion on the noise measurement theory is presented to illustrate the limitation of the noise measurement system. The extracted noise sources were studied for their geometry and biasing dependences and by implementing additional noise sources into the small-signal RFCMOS model, accurate HF noise simulation for the transistor can be achieved. Verilog-A is used for the coding of the additional noise sources into the RFCMOS model and the added noise source will compensate the underestimation of the channel thermal noise from the BSIM3v3 core model. Simulated noise circles and the measured noise figures are plotted at other source impedances to show that all the noise parameters are simulated accurately. The biasing and geometry dependences of the measured and simulated noise parameters are presented to demonstrate the scalability of the developed HF noise model. The scalability feature in HF noise model can be implemented into the process design kit (PDK) so that more powerful PDK can be developed for the circuit designers to optimize and simulate their circuit design that requires stringent noise specifications. The accurate noise simulation can ensure better chance of success and reduce the number of tape-out and design cycle time.