| 研究実績の概要 |
The research aims to reveal new properties of Si nanodevices, emerging due to the high doping with both donors and acceptors. In such systems, the interplay between donors and acceptors in small scale may lead to a behavior similar to "semimetals".
We have addressed this research by two main approaches (plans): (A) by fabrication of highly-doped nanodevices (doped both with P-donors and B-acceptors) and their electrical characterization; (B) by analyzing co-doped Si nanowire devices using first-principles and semi-empirical simulations.
We succeeded in introducing a rapid thermal annealing (RTA) system to process a more controllable doping profile in silicon-on-insulator pn and pin diodes. After the optimization of this process, the Esaki diode characteristics could be confirmed and further analysis is currently under way, based mainly on low-temperature modeling of band-to-band tunneling current features. (Preliminary results were reported in D. Moraru et al., inter-Academia 2021 Conference.)
In terms of simulations, we investigated the role of multiple B-acceptors in electron transport through a-few-donor clusters in Si nanowire transistors (Appl. Phys. Express 2021). Based on this background, we also studied pn and pin Si nanowire diodes, containing a P-donor/B-acceptor pair in different configurations. The analysis was then focused on correlating electrical characteristics, density-of-state spectra and carrier wave functions, in order to reveal the impact of the discrete dopants in band-to-band tunneling transport. (Preliminary results were reported in JSAP 69th Meeting.)
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