原子スケールの欠陥を測定する新しいツールで、トランジスタの限界を特定(New tool measures atomic scale defects, identifies transistor limitations)

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高度な電子デバイスの実現につながる可能性があると研究者が発表 Approach may enable advanced electronic devices, researchers say

2022-05-23 ペンシルベニア州立大学(PennState)

The work was featured as the cover of the Applied Physics Letters of the issue in which it appeared.  Credit: Kelby Hochreither/Penn State. All Rights Reserved.

半導体材料の欠陥を研究する新しい技術は、先端材料の原子レベルの限界を明らかにすることで、電子デバイスのスピード、パワー、性能の向上につながる可能性があります。
研究チームが開発したこの解析ツールは、新しい材料の欠陥を検出・測定するために、そのような測定で通常用いられるものよりはるかに小さい磁場と周波数を利用し、電子と近傍の磁性核との磁気相互作用に関する構造情報を従来よりも簡単な方法で提供します。

<関連情報>

4H-SiCの周波数掃引型スピン依存性再結合における等方的超微細相互作用の変調による中間スピンペア緩和 Intermediate spin pair relaxation through modulation of isotropic hyperfine interaction in frequency-swept spin-dependent recombination in 4H–SiC

J. P. Ashton, B. R. Manning, S. J. Moxim, F. V. Sharov, P. M. Lenahan, and J. T. Ryan
Applied Physics Letters  Published:07 February 2022
DOI:https://doi.org/10.1063/5.0084378

ABSTRACT

Electrically detected magnetic resonance (EDMR) measurements have been extended to sub-mT magnetic fields through utilization of frequency sweeping of the oscillating magnetic field, where conventional electron paramagnetic resonance-based measurements traditionally utilize magnetic field magnitude ramping. In spin-dependent transport measurements in devices, an oftentimes pervasive near-zero field magnetoresistance effect overwhelms the sub-mT regime. This magnetoresistance effect is independent of the RF drive. Thus, by utilizing a constant DC magnetic field and a frequency sweep of the RF magnetic field, the magnetoresistance effect is not detected, leaving only the EDMR response. Interesting EDMR-based phenomena emerge at sub-mT fields when the oscillating field magnitude approaches the static field, such as multiple-photon transitions caused by the emergence of Floquet spin states and Bloch–Siegert shifts. A spectral-narrowing effect also emerges as the static field is reduced. In this work, we show that the narrowing of the frequency-swept EDMR response with static field can be modeled by changes in intermediate spin-pair relaxation through modulation of hyperfine fields caused by stochastic perturbations from the environment. We utilize recently developed theory to model the relaxation of spin pairs and show that stochastic interactions of the electron spin with the environment yield both Floquet spin states and changes in intermediate spin-pair relaxation.

This work at Penn State was supported by the U.S. Army Research Laboratory. Any opinions, findings, conclusions, or other recommendations expressed herein are those of the authors and do not necessarily reflect the views of the U.S. Army Research Laboratory. This work was also supported by the Air Force Office of Scientific Research under Award No. FA9550-17-1-0242.

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