In order to overcome the small current drivability of a tunneling field-effect transistor (TFET), we have introduced a TFET with the SiGe body and elevated Si drain region. The proposed TFET features large on-current and lower subthreshold swing (SS) compared with the Si TFET. Also, by using elevated Si drain region, it is expected that ambipolar current can be suppressed. Through the technology computer aided design (TCAD) simulation, the characteristics of the proposed TFET have been investigated to confirm its superiority in performance. The proposed TFET structure enables self-aligned doping process and has a strong immunity to short-channel effects compared with the conventional TFET. In addition, we have confirmed that both n-and p-channel characteristics can be simultaneously improved by using the proposed TFET.

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Tunneling Field Effect Transistors (TFETs) are considered as a candidate for low power applications. However, most of TFETs have been researched on only for long channels due to the misalignment problem that occurs during the source/drain doping process in device fabrication. Thus, a new method is proposed for the fabrication of TFETs in nanoscale regions. This proposed fabrication process does not need an additional mask to define the source/drain regions, and makes it possible to form a self-aligned source/drain doping process. In addition, through TCAD simulation, the electrical characteristics of a TFET with dopant engineering and a rounded gate edge shape for a higher on/off current ratio were investigated. As a result, the TFET showed the properties of a larger on-current, a lower average subthreshold swing (58.5 mV/dec), and a 30-fold smaller leakage current compared to the conventional TFET The TFET with dopant engineering and a rounded gate edge shape can also be fabricated simply through the proposed fabrication process.

In this paper, the total drain current (I D) of a tunnel FET (TFET) is decomposed into each current component with different origins to analyze the I D formation mechanisms of the TFET as a function of gate voltage (V GS). Transfer characteristics are firstly extracted with fabricated Silicon channel TFETs (Si TFETs) and silicon germanium channel TFETs (SiGe TFETs) at various temperatures. The subthreshold swings (SS) of both Si TFETs and SiGe TFETs get degraded and the SSs of SiGe TFETs get degraded more as temperature becomes higher. Then, all the I Ds measured at various temperatures are decomposed into each current component through technology computer aided design (TCAD) simulations with a good agreement with experimental data. As a result, it is revealed that Shockley–Read–Hall (SRH) recombination mainly contribute to the I D of a TFET before band to band tunneling (BTBT) occurs. Furthermore, the SS degradation by high temperature is explained successfully by the SRH recombination with electric field dependence.

In order to improve the internal quantum efficiency of GaN-based LEDs, a LED structure featuring a p-type trench in the multi-quantum well (MQW) is proposed. This structure has effects on spreading holes into the MQW and reducing the quantum-confined stark effect (QCSE). In addition, two simple fabrication methods using electron-beam (e-beam) lithography or selective wet etching for manufacturing the p-type structure are also proposed. From the measurement results of the manufactured GaN-based LEDs, it is confirmed that the proposed structure using e-beam lithography or selective wet etching shows improved light output power compared to the conventional structure because of more uniform hole distribution. It is also confirmed that the proposed structure formed by e-beam lithography has a significant effect on strain relaxation and reduction in the QCSE from the electro-luminescence measurement.