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Description
Ultra deep-submicron (UDSM) technologies are widely recognized for satellite constellations and other aerospace applications. Besides the advanced performance characteristics, 7-nm FinFET technology represents a local minimum in alpha-particle Soft-Error Rate (SER) compared to the previous nodes and the 5-nm node [1], which makes the technology very attractive for aerospace applications. The INFINIT (Irradiation assessment of N7 FINfet technology for Innovative digital Telecom applications) project is aimed at gaining a deep understanding of the 7-nm FinFET process technology for use in digital space applications.
Two-photon absorption (TPA) laser technique is attractive for quick and non-destructive estimation of Single Event Effects sensitivity. Based on the experience with a 65 nm CMOS Analog-to-digital converter (ADC), the following requirements and recommendations can be derived for FinFET devices:
1) Due to thin gate insulators and small fin height, the vertical laser beam source positioning should be as accurate as ~50 nm or even better to operate without damage to the insulator, however, it would increase the complexity and the cost, and introduce very strong requirements for the stabilization of the measurement equipment,
2) The channel stop doping (CSD) (M. P. King, et al. [2]) is used for some FinFET technologies, which changes the dependence of the threshold pulse energy on the vertical beam source positioning. Fig. 1 shows the qualitative representation of the issue.
3) Laser spot sizes correspond not to a single device, but to an area encompassing one or multiple standard cells, which complicates the Single Event Effects (SEE) sensitivity mapping of individual standard cells,
4) Polarization dependence reported by Landen D. Ryder, et al., [3] should be taken into account.
The SRAM blocks and SET test structures from the INFINIT Radiation Effect Test Vehicle Digital (RETVD) can be used for the study of these effects.
References
[1] B. Narasimham, V. Chaudhary, M. Smith and L. Tsau, "Scaling Trends in the Soft Error Rate of SRAMs from Planar to 5-nm FinFET," in 2021 IEEE International Reliability Physics Symposium (IRPS), 2021.
[2] M. P. King, X. Wu, M. Eller, S. Samavedam, M. R. Shaneyfelt, et al., “Analysis of TID Process, Geometry, and Bias Condition Dependence in 14-nm FinFETs and Implications for RF and SRAM Performance,” IEEE Transactions on Nuclear Science, vol. 64, no. 1, pp. 285-292, January 2017.
[3] Landen D. Ryder , Kaitlyn L. Ryder, Andrew L. Sternberg, John A. Kozub, Huiqi Gong, En Xia Zhang, et al., “Polarization Dependence of Pulsed Laser-Induced SEEs in SOI FinFETs,” ,” IEEE Transations on Nuclear Science, vol. 67, no. 1, pp. 38-43, January 2020.
