1. Introduction and Motivation:
Modern microelectronic devices, particularly memories and programmable logic, face significant challenges in harsh radiation environments. While traditional single-event upsets (SEUs) pose a threat, Geometric Multiple-Bit Upsets (GMBUs), where a single energetic particle strike causes errors in multiple physically adjacent bits, are increasingly concerning. This project aims to investigate the underlying mechanisms driving GMBU formation in advanced microelectronics. A deeper understanding of these mechanisms is crucial for developing effective mitigation strategies and ensuring the reliability of critical systems in space, aerospace, and high-energy physics applications.
2. Background:
GMBUs are a complex phenomenon influenced by several factors, including:
* Device Geometry: The physical layout of memory cells or logic elements, including bit interleaving schemes, strongly influences GMBU susceptibility.
* Radiation Characteristics: The energy, Linear Energy Transfer (LET), and angle of incidence of the impacting particle affect the size and shape of the resulting ionization track.
* Material Properties: The properties of the semiconductor material (e.g., silicon, silicon-on-insulator (SOI)) influence charge generation, transport, and collection.
* Circuit Design: The design of the memory cell or logic gate affects its sensitivity to charge disturbances.
* Manufacturing Variations: Process variations can lead to non-uniformities in device characteristics, influencing GMBU occurrence.
Existing models often treat GMBUs as a statistical phenomenon. This project seeks to develop a more mechanistic understanding.
3. Research Objectives:
This project will investigate the mechanisms of GMBU formation through a combination of of simulation and experimentation, including the possibility of :
* TCAD Simulations: Utilizing Technology Computer-Aided Design (TCAD) tools to simulate particle strikes and charge transport within the device structure.
* Focused Laser Testing: Employing focused laser beams to emulate radiation strikes and observe the resulting electrical effects.
* Radiation Testing: Conducting experiments using proton, heavy ion, or neutron irradiation to characterize GMBU occurrence under realistic conditions.
* Microscopic Analysis: Using techniques such as Focused Ion Beam (FIB) microscopy or Transmission Electron Microscopy (TEM) to analyze device structures and identify potential GMBU-sensitive regions.
* Statistical Modeling: Developing advanced statistical models that incorporate the mechanistic understanding gained from simulations and experiments.
* Circuit Modeling: Developing SPICE-level circuit models to simulate GMBU effects on circuit performance.
Specifically, the project aims to:
* Identify the key device parameters and radiation conditions that most significantly influence GMBU formation.
* Characterize the spatial distribution and size of GMBUs.
* Develop a physics-based model that accurately predicts GMBU rates under different radiation environments.
* Investigate the effectiveness of various mitigation techniques, such as error-correcting codes (ECC) and layout optimization, in reducing GMBU susceptibility.
4. Methodology:
The research will proceed through the following stages:
* Literature Review: A comprehensive review of existing literature on GMBUs, radiation effects, and device physics.
* Simulation Setup (If applicable): Development of accurate TCAD models of the target device structure. This includes defining the geometry, material properties, and doping profiles.
* Experimental Design (If applicable): Design of experiments for radiation testing or focused laser testing. This includes selecting appropriate radiation sources, test structures, and measurement techniques.
* Data Collection and Analysis: Collection of simulation or experimental data on GMBU occurrence. This includes analyzing the spatial distribution, size, and frequency of GMBUs.
* Model Development: Development of a physics-based model that describes the mechanisms of GMBU formation. This model will be validated against simulation and experimental data.
* Mitigation Analysis: Evaluation of different mitigation techniques using the developed model.
* Reporting and Dissemination: Preparation of research reports, presentations, and publications.
5. Expected Outcomes:
The successful completion of this project will result in:
* A deeper understanding of the mechanisms driving GMBU formation in modern microelectronics.
* A physics-based model that accurately predicts GMBU rates under different radiation environments.
* Identification of key device parameters and radiation conditions that influence GMBU susceptibility.
* Evaluation of the effectiveness of various mitigation techniques in reducing GMBU susceptibility.
* Publications in peer-reviewed journals and presentations at scientific conferences.
radiation effects in electronics; single-event effects mechanisms; multiple-bit upsets; hamming codes; error correction
Additional Benefits
relocation
Awardees who reside more than 50 miles from their host laboratory and remain on tenure for at least six months are eligible for paid relocation to within the vicinity of their host laboratory.
health insurance
A group health insurance program is available to awardees and their qualifying dependents in the United States.