Characterization of Prompt Dose- and Pulsed-Laser-Induced Transient Photocurrent from Integrated Circuits Using the On-Chip Photocurrent Measurement Circuit

Abstract

This research presents a methodology for on-chip measurement of transient photocurrent for technology characterization and mechanism discovery with implementation and demonstration in two sub-50nm silicon-on-insulator (SOI) technologies. Transient photocurrent generated in the depletion region of integrated circuit transistors has traditionally been characterizable through off-chip probing of large arrays of photocurrent generation structures. However, the Moore's Law scaling of technologies and shrinking of depletion regions in partially-depleted silicon-on-insulator (PD-SOI) and fully-depleted silicon-on-insulator (FD-SOI) technologies has made off-chip measurement techniques intractable due to attenuation and signal-to-noise (SNR) limitations. The inability to characterize transient photocurrent in these technologies through traditional methods has motivated this research in the development of on-chip measurement methods through specially-designed, radiation-aware mixed-signal components. A circuit has been developed, using these methods, and fabricated in two sub-50nm SOI technologies, which is referred to as the photocurrent measurement circuit (PMC). Experimentally obtained data from from flash x-ray (FXR) and infrared pulsed-laser sources on a 22nm FD-SOI and 45nm PD-SOI PMC presented. The results indicate successful implementation of the methodologies, resulting in data acquisition with the PMC in both technologies with detection of transistor level photocurrent mechanisms across twelve different sub-50nm SOI targets. These results are corroborated by 3D technology computer-aided design (TCAD) simulations, as well as schematic-level simulations in Cadence Virtuoso.