subthresholdläpinäkyvyyteen

Subthreshold leakage current is a phenomenon observed in semiconductor devices, particularly in transistors, where a small amount of current flows even when the device is intended to be in the "off" state. This "off" state is defined by a gate voltage that is below a certain threshold, known as the threshold voltage. While ideally, no current should flow below the threshold voltage, in reality, a small, non-zero current persists.

This subthreshold leakage is primarily due to the diffusion of charge carriers across the channel region of the transistor. Even when the gate voltage is insufficient to create a strong inversion layer, there are still a small number of minority carriers present that can diffuse from the source to the drain due to thermal energy and concentration gradients. The rate of this diffusion is exponentially dependent on the gate voltage.

The impact of subthreshold leakage is most significant in integrated circuits, especially as device dimensions shrink and power supply voltages are reduced. In low-power applications, this leakage current can contribute substantially to the overall static power consumption of a chip. This necessitates the design of circuits and transistors that minimize subthreshold leakage through techniques like body biasing or the use of materials with higher threshold voltages. Understanding and controlling subthreshold leakage is crucial for optimizing the performance and energy efficiency of modern electronic devices.