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By scanning the charge-deposition profile produced by a pulsed laser throughout a device, the spatially dependent charge-collection efficiency (CCE) can be determined. This is demonstrated by extracting the depth-dependent CCE in two photodiodes. The resulting collection efficiency curves are found to be consistent with their device structures and the expected charge-collection mechanisms. By applying the efficiency curves to the charge-deposition curves for both heavy ions and pulsed X-rays, the calculated collected charge values show very good agreement with experimental results. This suggests that the profiles extracted using the laser can help predict charge-collection data from other excitation sources and could improve modeling efforts by determining sensitive volumes. [ABSTRACT FROM AUTHOR]

A novel approach for two-photon absorption (TPA) pulsed-laser testing produces extended charge deposition profiles that are analogous to those produced by heavy ions. In this approach, which utilizes an axicon rather than a spherical lens, the conventional Gaussian beam is replaced by a quasi-Bessel beam. The key feature of a quasi-Bessel beam, relevant to pulsed-laser single-event effects (PL-SEE) studies, is that its radial size (1~μm) remains constant over the axial length of the beam (several 100 s of μm) resulting in a charge-deposition profile that more closely mimics that produced by a heavy ion. This elongated charge distribution directly lends itself to a simple and intuitive description in terms of linear-energy transfer (LET), facilitating laser/ion correlation studies. Experimental results comparing a conventional TPA PL-SEE focusing geometry and the axicon focusing geometry are presented for three different test vehicles: a 45-nm silicon-on-insulator (SOI) nFET, a bulk silicon photodiode, and an LM124 operational amplifier. By using the axicon approach, strong laser/ion correlation is observed in the silicon photodiode for single-event transients (SET) across a wide range of LETs. The correlation is achieved by “tuning” the laser to the desired LET rather than relying on preexisting heavy-ion data, and therefore, this approach holds promise as a predictive tool. [ABSTRACT FROM AUTHOR]

Silicon-germanium heterojunction bipolar transistor (SiGe HBT) models are used in technology computer aided design (TCAD) to investigate single event transients induced by heavy-ion broadbeam and pulsed-laser two-photon absorption sources. A comparison between transient waveforms is provided, the proper extraction of heavy-ion broadbeam transients is discussed (along with circuit implications), and basic laser strike profiles are implemented in TCAD to provide insight into future design practices for simulation software to be used to describe laser-induced upsets in terms of an effective linear energy transfer (LET). [ABSTRACT FROM PUBLISHER]