MOSFETteknik

MOSFETteknik is the technology and engineering of metal-oxide-semiconductor field-effect transistors (MOSFETs) and their use in electronic circuits. A MOSFET regulates current in a semiconductor channel with an electric field applied to a gate insulated from the channel by an oxide layer. This yields high input impedance and scalability, making MOSFETs foundational to modern electronics.

The MOSFET was developed in the 1960s at Bell Labs, leading to early devices and integrated circuits. Over time the industry adopted enhancement-mode devices and, with CMOS, combined n-type and p-type transistors to reduce power consumption in digital logic.

There are two main families: enhancement-mode and depletion-mode, and two carrier types: NMOS and PMOS. In enhancement-mode devices, a channel forms when the gate voltage exceeds a threshold; in depletion-mode devices, a channel exists at zero gate voltage and is altered by bias. The gate oxide, typically silicon dioxide or a high-k dielectric, insulates the gate while allowing electric field control of the channel.

Fabrication uses planar silicon processes, including lithography and ion implantation, with gate formation and passivation. Modern MOSFETs employ aggressive scaling and architectures such as FinFETs, which wrap the channel to improve control. CMOS integration enables high transistor density and low static power by combining NMOS and PMOS on the same substrate.

Applications span digital logic, microprocessors, memory, and power electronics. Power MOSFETs switch high currents and voltages in power supplies, motor drives, and audio amplifiers. Development in MOSFETteknik focuses on scaling, leakage reduction, reliability, and integration with new materials and three-dimensional layouts.