A Ge/Si heterojunction L-shaped tunnel field-effect transistor combined with hetero-gate-dielectric (GHL-TFET) is proposed and investigated by TCAD simulation. Current-voltage characteristics, energy-band diagrams, and the distribution of the band-to-band tunneling (BTBT) generation rate of GHL-TFET are analyzed. In addition, the effect of the vertical channel width on the ON-current is studied and the thickness of the gate dielectric is optimized for better suppression of ambipolar current. Moreover, analog/RF figure-of-merits of GHL-TFET are also investigated in terms of the cut-off frequency and gain bandwidth production. Simulation results indicate that the ON-current of GHL-TFET is increased by about three orders of magnitude compared with that of the conventional L-shaped TFET. Besides, the introduction of the hetero-gate-dielectric not only suppresses the ambipolar current effectively but also improves the analog/RF performance drastically. It is demonstrated that the maximum cut-off frequency of GHL-TFET is about 160 GHz, which is 20 times higher than that of the conventional L-shaped TFET.

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With the massive use of computers, the growth and explosion of data has greatly promoted the development of artificial intelligence (AI). The rise of deep learning (DL) algorithms, such as convolutional neural networks (CNN), has provided radiation oncologists with many promising tools that can simplify the complex radiotherapy process in the clinical work of radiation oncology, improve the accuracy and objectivity of diagnosis, and reduce the workload, thus enabling clinicians to spend more time on advanced decision-making tasks. As the development of DL gets closer to clinical practice, radiation oncologists will need to be more familiar with its principles to properly evaluate and use this powerful tool. In this paper, we explain the development and basic concepts of AI and discuss its application in radiation oncology based on different task categories of DL algorithms. This work clarifies the possibility of further development of DL in radiation oncology.

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The L-shaped tunnel field-effect transistor (LTFET) improves current drivability significantly by transforming the path of the band-to-band tunnelling from point-tunnelling to line-tunnelling, but meanwhile, the gate-source overlapped structure of LTFET brings about a larger active area of interface trap charges (ITCs). In this paper, the impact of ITCs on LTFET's characteristics is investigated in terms of the electric field, dc, analogue/RF, linearity and transient performance. From TCAD simulation results, it is found that for conventional LTFET, different types of ITCs lead to distinct variations in I-V characteristics, subthreshold swing, transconductance, parasitic capacitances, cutoff frequency, linearity parameters such as V IP2 , V IP3 , I IP3 , and I MD3 and the fall propagation delay (t pHL). To improve the device stability, heterogeneous gate dielectric (HGD) structure is introduced into LTFET. From comparison results, it is found that benefiting from the improved gate controllability near the tunnelling junction, HGD-LTFET not only improves dc, analogue/RF, linearity and transient performance but also effectively suppresses the variation caused by ITCs thus has better stability. Therefore, HGD-LTFET is a very attractive choice in future low-power and high-frequency applications.