This brief deals with the impact of spin-transfer torque magnetic random access memory (STT-MRAM) cell based on double-barrier magnetic tunnel junction (DMTJ) on the performance of a two-layer multilayer perceptron (MLP) neural network. The DMTJ-based cell is benchmarked against the conventional single-barrier MTJ (SMTJ) counterpart by means of a comprehensive evaluation carried out through a state-of-the-art device-to-algorithm simulation framework. The benchmark is based on the MNIST handwritten dataset, Verilog-A MTJ compact models developed by our group, and 0.8 V FinFET technology. Our results point out that the use of DMTJ-based STT-MRAM cells to implement digital embedded non-volatile memory (eNVM) synaptic core allows write/read energy and latency improvements of about 53%/61% and 66%/17%, respectively, as compared to the SMTJ-based equivalent design. This is achieved by ensuring a reduced area footprint and a learning accuracy of about 91%. Such results make the DMTJ-based STT-MRAM cell a good eNVM option for neuro-inspired computing.

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This paper presents a detailed analysis on the impact of the emitter contact geometry on the performance of back contact-back junction (BC-BJ) c-Si solar cells by means of a TCAD-based electro-optical model. BC-BJ c-Si solar cells featuring a conventional linear-contact (LC) scheme and an advanced point-contact (PC) pattern are considered. In addition, the introduction of a selective emitter (SE) design in the PC structure and the effect of including multiple contacts in the emitter region of the considered BC-BJ solar cells are also investigated.

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Interdigitated back contact (IBC) crystalline silicon (c-Si) solar cells are attracting a lot of attention because of their capability to reach world record conversion efficiency. Because of the relatively complex contact pattern, their design and optimization typically require advanced numerical simulation tools. In this work, a TCAD-based simulation platform has been developed to account accurately and in detail the optical and passivation mechanisms of front texturization. Its validation has been carried out with respect to a novel homo-junction IBC c-Si solar cell based on ion implantation and epitaxial growth, comparing measured and simulated reflectance, transmittance, internal quantum efficiency, external quantum efficiency spectra, and current density–voltage characteristics. As a result of the calibration process, the opto-electrical losses of the investigated device have been identified quantitatively and qualitatively. Then, an optimization study about the optimal front surface field (FSF) doping, front-side texturing morphology, and rear side geometry has been performed. The proposed simulation platform can be potentially deployed to model other solar cell architectures than homo-junction IBC devices (e.g., passivated emitter rear cell, passivated emitter rear locally diffused cell, hetero-IBC cell). Simulation results show that a not-smoothed pyramid-textured front interface and an optimal FSF doping are mandatory to minimize both the optical and the recombination losses in the considered IBC cell and, consequently, to maximize the conversion efficiency. Similarly, it has been showed that recombination losses are affected more by the doping profile rather than the surface smoothing. Moreover, the performed investigation reveals that the optimal FSF doping is almost independent from the front texturing morphology and FSF passivation quality. According to this result, it has been demonstrated that an IBC cell featuring an optimal FSF doping does not exhibit a significant efficiency improvement when the FSF passivation quality strongly improves, proving that IBC cell designs based on low-doped FSF require a very outstanding passivation quality to be competitive. Deploying an optimization algorithm, the adoption of an optimized rear side geometry can potentially lead to an efficiency improvement of about 1%abs as compared with the reference IBC solar cell. Further, by improving both emitter and c-Si bulk quality, a 22.84% efficient solar cell for 280-μm thick c-Si bulk was simulated.@en