Insights into the impact of random dopant fluctuation on ferroelectric germanium source vertical TFET

• Published in: Materials science & engineering. B, Solid-state materials for advanced technology Solid-state materials for advanced technology, 2024-01, Vol.299, p.116994, Article 116994
• Main Authors: Vanlalawmpuia, K., Ghosh, Puja, Bhowmick, Brinda
• Format: Article
• Language: English
• Subjects: Ferroelectric; Random dopant fluctuation; Threshold voltage variation; Variability; vertical TFET
• ISSN: 0921-5107; 1873-4944
• DOI: 10.1016/j.mseb.2023.116994

•The study focuses on how random dopant fluctuation (RDF) affects the performance of ferroelectric Germanium source vertical tunnel field-effect transistor (FE GeS-vTFET) using a 3-D Technology Computer Aided Design (TCAD) simulation.•Variations in critical parameters such as on-state current (σION), off-state leakage current (σIOFF), current ratio (σION/IOFF), subthreshold swing (σSS), threshold voltage (σVTH), total gate capacitance (σCgg), transconductance (σgm), and cut-off frequency (σfT) are analyzed for different source doping concentrations and source thicknesses due to RDF effects.•The findings reveal an increasing trend in RDF with higher source doping concentration. The on-current increases approximately 1.075 times, while off-state leakage current increases around 3.349 times as doping concentration goes from 1 × 1020 /cm3 to 3 × 1020 /cm3 for a Germanium source thickness of 12 nm.•RDF within the source region contributes significantly to threshold voltage variations, accounting for about 92% of the observed changes across all regions.•The FE GeS-vTFET demonstrates superior immunity to RDF compared to other field- effect transistors, with a substantial 48.72% reduction in threshold voltage variation (σVTH) compared to Ge-Source vertical tunnel FET without the implementation of FE layer.•The study also investigates the influence of temperature on the switching properties of FE GeS-vTFET, revealing an exponential decrease in switching time with increasing temperature for Si:HfO2 FE film. This paper investigates the effect of random dopant fluctuation (RDF) on the performance of ferroelectric Germanium source vertical tunnel field effect transistor (FE GeS-vTFET) using 3-D device simulation. The variation in the on-state current (σION), off-state leakage current (σIOFF), current ratio σ(ION/IOFF), subthreshold swing (σSS), threshold voltage (σVTH), total gate capacitance (σCgg), transconductance (σgm) and cut-off frequency (σfT) for different source doping concentration and source thickness due to the effect of RDF are evaluated. The findings indicate an increasing tendency in RDF with higher doping concentration in the source region. The variation in the on-current is from 0.2173 mA to 0.2337 mA (∼1.075 times higher), and σIOFF varies from 4.939 fA to 16.545 fA (∼3.349 times higher) from 1 × 1020 /cm3 to 3 × 1020 /cm3 doping concentration, respectively for Germanium source thickness of 12 nm. RDF within the source region mainly contributes to the