Type of Document	Dissertation
Author	Hooten, Nicholas C
Author's Email Address	nicholas.c.hooten@vanderbilt.edu
URN	etd-03312014-121311
Title	Charge Collection Mechanisms in Silicon Devices During High-Level Carrier Generation Events
Degree	PhD
Department	Electrical Engineering
Advisory Committee	Advisor Name Title Robert A. Reed Committee Chair Arthur F. Witulski Committee Member John A. Kozub Committee Member Robert A. Weller Committee Member Ronald D. Schrimpf Committee Member
Keywords	SEE single-event effects radiation effects in microelectronics Two-photon absorption laser testing for SEE SEE laser testing device-level current transients
Date of Defense	2014-03-21
Availability	unrestricted
Abstract When ionizing radiation interacts with a semiconductor device, the resulting generation and collection of excess charge carriers can result in a brief transient current at the device terminals. These transient current pulses can negatively impact device and circuit operation, which poses a critical reliability concern for systems where continued, reliable operation is tantamount to success. A thorough understanding of charge collection mechanisms provides device and circuit designers with the tools to make well-informed decisions about the designs of microelectronic components intended for spaceflight applications and other harsh radiation environments. In this work, charge collection mechanisms following high-level carrier generation conditions (which could be caused by many heavy ions in the space radiation environment) are investigated using experimental measurements, device-level numerical simulations, and recent theoretical developments. Broadbeam heavy-ion irradiation and backside two-photon absorption laser exposure on several bulk-silicon test structures is used to emphasize the significance of depletion region potential modulation on the overall device response. The device response is measured using high-speed transient capture methods, and, when needed, device-level simulations are used as a means to explain the overall device response. Key findings reveal that significant modulation of the device depletion region can lead to the saturation of current transient peaks, highly efficient charge-collection processes, and, in cases where multiple junctions are in close proximity, the recovery of the struck junction may lead to a simultaneous response at a nearby junction. These discussions are primarily focused on the response of a reverse-biased n-well over p-substrate diode, which are commonly found in many semiconductor devices. However, because devices and circuits typically rely on the interaction of multiple semiconductor junctions, the effects of n-well potential modulation on the device-response of a PMOSFET following a high-level carrier generation event is also investigated through both experimental measurements and device-level simulations. Where applicable, these insights are used to inform the development of predictive analytical models for the peak transient current and total collected charge following a high-level carrier generation event.
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