Giving to CREOL CREOL, The College of Optics & Photonics

Seminar: "Using Pulsed-Laser Excitation to Simulate Radiation Effects in Microelectronics" by Joel Hales

Friday, October 26, 2018 2:00 PM to 3:00 PM
CREOL Room 102


Electronic systems operating in space are exposed to radiation in the form of energetic charged particles. When these particles pass through the sensitive volume of an electronic device, they liberate electrons from the constituent atoms and can cause a variety of potentially harmful effects, which are referred to as single-event effects (SEEs). Assessing the impact of ionization-induced SEEs has traditionally been conducted via exposure of the device to a heavy-ion beam generated by a particle accelerator. However, approaches using pulsed-laser excitation to generate charge carriers in semiconductors have found widespread usage in the simulation of radiation-induced SEEs. These approaches are attractive because they generate a known carrier distribution (CD) in a well-defined spatial location within the device while being laboratory-based and cost effective. Furthermore, the use of two-photon absorption (2PA) allows for laser access through the backside of the wafer thereby avoiding interference from packaging and metal overlayers which are common in most devices. However, difficulties in correlating laser-induced charge generation to an equivalent heavy-ion result has limited the 2PA SEE approach to mainly qualitative studies.

In this talk, we will discuss our recent efforts towards accurately simulating heavy-ion-induced radiation effects using the 2PA SEE approach. The two main obstacles to overcome were the complexities associated with accurately calculating the CD generated by 2PA and the marked differences in the CDs generated by the two excitation mechanisms. We have addressed the former through careful characterization of the laser pulse delivered to the device and the establishment of accurate numerical methods that accurately reproduce experimental 2PA SEE results. By using an equivalent charge deposition approach, we have addressed the issue of disparate CDs and have shown strong laser-ion correlation for both a bulk silicon diode as well as more complex device technologies. We will also discuss recent work targeting a more challenging problem of correlating transient responses of devices generated using these two mechanisms. Overall, this laser-based approach is capable of quantitatively predicting radiation effects and can be used to complement or, in certain cases, supplant traditional heavy-ion testing.


Dr. Joel Hales is a scientific consultant for the Naval Research Laboratory where he participates in the experimental design, testing, and physics-based modeling aimed at predicting radiation effects in micro- and nano-electronic devices. Previously he served as a principal research scientist at the Georgia Institute of Technology where he acted as chief researcher in two multi-investigator DARPA-supported programs that centered on using organic materials in next-generation all-optical communications systems.  Dr. Hales possesses 15+ years of research experience in the area of optics and photonics and has extensive experience working across disciplines, which include chemistry, materials science, optical sciences, physics, and electrical engineering. Dr. Hales received his PhD from the University of Central Florida in Optical Sciences and is a long-time member of the Optical Society of America, the American Physical Society, the Institute of Electrical and Electronics Engineers, and the American Chemical Society.

For additional information:

Eric Vanstryland

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