Agilent Technologies Inc. announced that the Agilent B1530 Waveform Generator/Fast Measurement Unit (WGFMU)  was used by the Indian Institute of Technology (IIT) Bombay to make ultrafast measurements of  negative bias temperature instability (NBTI) degradation in deeply scaled high-K metal gate (HKMG) CMOS devices for a wide variety of DC and AC stress tests.

ITT Bombay presented the findings of its research in a paper delivered this week at the IEEE International Reliability Physics Symposium in Hawaii. The Agilent-supported lab at IIT Bombay included usage of ab-initio modeling.

NBTI is a serious reliability concern and affects the performance of CMOS IC chips used in electronic products such as laptops, tablets and cell phones. The phenomenon degrades the performance of transistors, the basic logic elements inside semiconductor ICs.

To determine the effect of NBTI during operation of a CMOS IC over a product’s lifetime (typically a few years), NBTI degradation is measured under accelerated voltage-induced-stress conditions. The measured results are then extrapolated to the end of the product’s life under use conditions using suitable models. The IC industry has now recognized the necessity of performing ultrafast measurements for accurate estimation of CMOS device degradation due to NBTI.

“NBTI remains a serious issue for sub-20 nm CMOS technology nodes,” said Souvik Mahapatra, professor, electrical engineering department, IIT Bombay. “The Agilent B1530 WGFMU is a very stable platform for making ultrafast DC and AC NBTI measurements. The programmability feature of the WGFMU has enabled us to customize measurements to explore different aspects of the underlying physical phenomenon. This has in turn helped us to develop the correct physics-based model to predict NBTI for different DC and AC conditions.”

The unique data collected helped the researchers at IIT Bombay develop a robust model for predicting NBTI induced CMOS device degradation during and after DC stress at different operating bias and temperature, and during AC stress at different operating bias, temperature, pulse duty cycle and frequency. Calibrated model parameters are obtained, which are used for reliable estimation of NBTI degradation at end of IC life under different operating conditions.

“NBTI is a serious reliability concern for scaled CMOS technologies,” said Sudhir Tangri, Agilent India country manager, Electronic Measurement Group. “Because of the availability of the Agilent B1530 and the WGFMU capability in Agilent-IIT device characterization lab, IIT Bombay could make ultrafast measurements of BTI degradation in deeply scaled HKMG devices for both DC and AC stress. We are extremely proud to be associated with such important research.”

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