Subthreshold conduction

About: Subthreshold conduction is a research topic. Over the lifetime, 6343 publications have been published within this topic receiving 131957 citations. The topic is also known as: Subthreshold leakage.

Capacitance Modeling in Dual Field-Plate Power GaN HEMT for Accurate Switching Behavior

Abstract: In this paper, a surface-potential-based compact model is proposed for the capacitance of an AlGaN/GaN high-electron mobility transistor (HEMT) dual field-plate (FP) structure, i.e., with gate and source FPs. FP incorporation in a HEMT gives an improvement in terms of enhanced breakdown voltage, reduced gate leakage, and so on, but it affects the capacitive nature of the device, particularly by bringing into existence in a subthreshold region of operation, a feedback miller capacitance between the gate and the drain, and also a capacitance between the drain and the source, therefore, affecting switching characteristics. Here, we model the bias dependence of the terminal capacitances, wherein the expressions developed for intrinsic charges required for capacitance derivation are analytical and physics-based in nature and valid for all regions of device operation. The proposed model, implemented in Verilog-A, is in excellent agreement with the measured data for different temperatures.

Subthreshold logical effort: a systematic framework for optimal subthreshold device sizing

Abstract: Subthreshold circuit designs have been demonstrated to be a successful alternative when ultra-low power consumption is paramount. However, the characteristics of MOS transistors in the subthreshold regime are significantly different from those in strong-inversion. This presents new challenges in design optimization, particularly in complex gates with stacks of transistors. In this paper, we demonstrate a new optimal sizing scheme for subthreshold designs which takes these issues into account. We derive a closed-form solution for the correct sizing of transistors in a stack, both in relation to other transistors in the stack, and to a single transistor with equivalent current drivability. Experimental results show that our framework provides a performance improvement of up to 13.5% over the conventional logical effort method on ISCAS benchmark circuits, while one component circuit demonstrated an improvement of 33.1%.

Low-Voltage Tunnel Transistors for Beyond CMOS Logic The use of interband tunneling to obtain steep subthreshold transistors at less than 0.5 V is described in this paper; underlying theory, key parameters, and optimization of performance are discussed.

Abstract: Steep subthreshold swing transistors based on interband tunneling are examined toward extending the per- formance of electronics systems. In particular, this review introduces and summarizes progress in the development of the tunnel field-effect transistors (TFETs) including its origin, cur- rent experimental and theoretical performance relative to the metal-oxide-semiconductor field-effect transistor (MOSFET), basic current-transport theory, design tradeoffs, and funda- mental challenges. The promise of the TFET is in its ability to provide higher drive current than the MOSFET as supply volt- ages approach 0.1 V.

Highly photosensitive thin film transistors based on a composite of poly(3-hexylthiophene) and titania nanoparticles

Abstract: Organic phototransistors based on a composite of P3HT and TiO2 nanoparticles have been fabricated, which show high photosensitivity, fast response, and stable performance under both visible and ultraviolet light illumination, and thus they are promising for applications as low cost photosensors. The transfer characteristic of each device exhibits a parallel shift to a positive gate voltage under light illumination, and the channel current increases up to three orders of magnitude in the subthreshold region. The shift in the threshold voltage of the device has a nonlinear relationship with light intensity, which can be attributed to the accumulation of electrons in the embedded TiO2 nanoparticles. It has been found that the device is extremely sensitive to weak light due to an integration effect. The relationship between the threshold voltage change and the intensity of light illumination can be fitted with a power law. An analytical model has been developed to describe the photosensitive behavior of the d...

Detailed investigation of n-channel enhancement 6H-SiC MOSFETs

Abstract: Basic MOSFET parameters like inversion layer mobility, threshold voltage, intrinsic mobility reduction factor and interface state density extracted from the subthreshold slope were examined in detail for 6H-SiC enhancement-mode n-channel MOSFETs. The inversion layer mobility and the threshold voltage were determined as a function of substrate doping concentration as well as device temperature. The interface state density was studied for different substrate doping concentrations. The inversion layer mobility was found to decrease strongly with increasing substrate doping. In contrast to earlier reports the inversion layer mobility decreases also with temperature. Furthermore, the threshold voltage depends more pronounced on substrate doping and temperature than theoretically expected. The interface state density extracted from the subthreshold slope increases significantly with substrate doping concentration. All these phenomena are consistently interpreted by the classical MOSFET behavior which is extended by acceptor like interface states. These states are located close to the conduction band and exhibit a density increasing drastically toward the band edge.