1/f Noise Measurements and SPICE Model Extraction For MOS Transistors

Silvaco noise amplifier.

Noise in semiconductor devices has a significant impact on circuits performances.

This is even more important in today’s low-voltage, high performance, mixed signal and RF designs.

The capability to measure and characterize semiconductor devices noise is a fundamental requirement for design.

Noise characterization is also important to monitor semiconductor processes quality.

Silvaco has been offering 1/f noise measurement and SPICE model noise parameters extraction solution for MOS transistors to its customers for several years.


UTMOST III measurements setup window.


This solution consists of:

  • S3245A noise amplifier specifically designed for high performance/high accuracy MOS transistor 1/f noise measurements.
  • UTMOST III software which includes 1/f noise measurement and SPICE models extraction.

Automatic I-V and 1/f noise measurements can be performed on wafer level or on packaged devices. Multiple DC bias points can be specified.

It is possible to setup the bias conditions, measurement frequency range, number of averages and other measurements conditions. These setups can be saved as a file to be used in the future.

Measurement at multiple bias points within a single measurement session is possible as well.

SPICE parameter extraction is performed by UTMOST by specifying the model type. UTMOST supports SmartSpice and HSPICE noise models NLEV=0,1,2,3 and the physical BSIM3v3 Noise model (Noimod=2).

The NOIMOD=2 model seems to provide better fits (Better than NLEV=2 standard SPICE model) for modeling flicker noise at different DC bias conditions. However the NOIMOD=2 model requires the collection of more data points. In order to find the bias dependency of the model UTMOST III will automatically collect noise data at different DC bias conditions.

The extracted noise parameters are fed back into special NOISE verification circuits and simulated using SmartSpice. This final step completes the verification of the extracted noise parameters.

Existing SPICE models accuracy can be verified as well by simulating noise characteristics.

BSIM3 (noimod=2) noise equation implemented in SPICE.


Multiple bias point noise measurement data.


UTMOST III measurements setup window.


Rev. 102207_03