Gate Voltage Dependence of Low Frequency Noise in Tunneling Field Effect Transistors.

In this paper, the dependency of low frequency noise as a function of the gate voltage was examined for tunneling field effect transistors (TFETs). When the level of gate voltage is low, the tunneling width of the TFETs is large. Thus, electrons move via the trap instead of tunneling directly. On the other hand, when the level of gate voltage is high, the tunneling width of the TFETs becomes narrow. Thus, when the gate voltage is low, the noise level of TFETs is high because electrons pass through the trap. However, when the gate voltage is high, electrons pass directly from valence band of source to conduction band of drain, so the noise level is low. Finding the voltage suitable for this TFET is important to determine the optimum conditions for generating BTBT when measuring TFETs and to reduce noise.

Investigation of Positive Bias Temperature Instability Characteristics of Fully Depleted Silicon on Insulator Tunneling Field Effect Transistor with High-k Dielectric Gate Stacks.

The positive bias temperature instability (PBTI) characteristics of fully depleted silicon on insulator (FD-SOI) tunneling field effect transistor (TFET) are investigated in comparison with those of metal oxide semiconductor field effect transistor (MOSFET) fabricated with the same technology process. Unlike some of the previously reported studies, in which the PBTI lifetime of TFET is much longer than that of MOSFET, in this study, the PBTI lifetime of TFET is found to be shorter than that of MOSFET. This result is very interesting, because degradation of electrical parameters of TFET is mainly affected by local traps near the source junction rather than global traps in the channel region. Large degradation of the electrical parameters of TFET due to PBTI stress would result from large fluctuation of the vertical electric field caused by traps near the source junction. This electric field fluctuation near the local region in TFET has more impact on electrical parameter degradation than channel conductivity fluctuation in MOSFET. Therefore, to improve the reliability characteristics of TFET, evaluation of PBTI characteristics and improvement of the quality of gate oxide near the source junction are essential.