Test circuit for bias temperature instability recovery measurements
US8229683B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 8, 2010 |
| Grant date | Jul 24, 2012 |
| Priority date | — |
| Expiry date | Dec 8, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/2856
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method, test circuit and test system provide measurements to accurately characterize threshold voltage changes due to negative bias temperature instability (NBTI) and positive bias temperature instability (PBTI). Both the bias temperature instability recovery profile and/or the bias temperature shifts due to rapid repetitions of stress application can be studied. In order to provide accurate measurements when stresses are applied at intervals on the order of tens of nanoseconds while avoiding unwanted recovery, and/or to achieve recovery profile sampling resolutions in the nanosecond range, multiple delay or ring oscillator frequency measurements are made using a delay line that is formed from delay elements that have delay variation substantially caused only by NBTI or PBTI effects. Devices in the delay elements are stressed, and then the delay line/ring oscillator is operated to measure a threshold voltage change for one or more measurement periods on the order of nanoseconds.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.