kynnysjännitykseen

Kynnysjännitys, known in English as threshold voltage, is a fundamental concept in semiconductor physics and electronics, particularly concerning field-effect transistors (FETs). It represents the minimum gate voltage required to create a conducting channel between the source and drain terminals of a FET. Below this voltage, the transistor is in an off-state, meaning very little current flows through it. Above the threshold voltage, the gate voltage electrostatically attracts charge carriers to the semiconductor-insulator interface, forming a conductive path that allows current to flow.

The value of the threshold voltage is crucial for determining the operating characteristics of a transistor. It influences the device's switching speed, power consumption, and sensitivity to variations in gate voltage. Factors such as the doping concentration of the semiconductor, the thickness and material of the gate insulator, and the presence of impurities or interface traps can all affect the threshold voltage. In integrated circuits, precisely controlling the threshold voltage is essential for ensuring reliable operation and achieving desired performance levels for different logic families and applications. Engineers often design circuits with specific threshold voltages to meet requirements for low-power operation or high-speed switching.