Random-Walk Drift-Diffusion Charge-Collection Model For Reverse-Biased Junctions Embedded in Circuits

Abstract

51st Annual IEEE International Nuclearand Space Radiation Effects Conference (NSREC), Paris, FRANCE, JUL 14-18, 2014International audienceA new computational model for charge transport based on parallelized random-walk drift-diffusion is proposed. This approach models the radiation-induced charge carriers as charge packets in a 3-D structure and the transport modeling are based on simple physical equations without any fitting parameter. This model has been dynamically coupled with a SPICE circuit simulator to take into account temporal variations of the electric fields in the charge collection process. Thus, the circuit electrical response modulates the charge collection efficiency. Three simulation cases have been explored and compared with TCAD simulations or radiation experiments in 65 nm technology to validate the accuracy of the proposed approach. These simulations demonstrate the capability of the proposed model to accurately estimate the soft error rate of complex structures, such as flip-flops over a large range of ionizing particle linear energy transfer. The proposed simulation methodology is also able to take into account charge-sharing phenomenon, and this point is highlighted by a specific investigation on the considered flip-flop

Charge Collection Physical Modeling for Soft Error Rate Computational Simulation in Digital Circuits

“…Cartoon (at five different times after the ionizing particle impact) illustrating the time evolution of the charge packets induced by a horizontal ionizing particle impacting two adjacent drains. The collection efficiency is different for these two drains since their biasing state is different (Reprinted with permission from Glorieux et al [12], of the charge packets induced by a horizontal ionizing particle in this two-node structure is shown at five different times after the ionizing particle impact. As evidenced in Figure 4, the collection efficiency of the two drains differs because they correspond to two different nodes in the circuit and their electrical potential (i.e., internal electric field) is not the same in this example.…”

“…This method has been successfully used in previous works, as shown in Refs. [12,13]. In the present work, we considerably improve this approach by a series of developments that make it capable of fast and intensive simulation of full circuits with an accuracy degree similar to that of the TCAD simulation.…”

Modeling Single Event Transients in Advanced Devices and ICs

“…The charge diffusion and collection mechanisms need to be modeled using analytical [68], [61], [77] or simplified physic equations [69], [80]. The transport mechanisms of the induced charges can be based on ambipolar diffusion model [91] taking into account recombination processes [68], [79] and carrier-carrier scattering phenomenon [61].…”

Radiation and COTS at ground level

“…3 in the case of an alpha particle striking a reverse-biased n+/p junction [22]: (1) the charge deposition by the energetic particle within the sensitive region, (2) the transport of the released charge into the device and (3)-(4) the charge collection in the active region of the device. In the following, we succinctly describe these different mechanisms, for a detailed presentation we invite the reader to consult ref.…”

“…Illustrations based on Monte Carlo random-walk drift-diffusion[22] (charge transport) and TCAD (current pulse) simulations.…”