metal-oxide semiconductor

A metal-oxide-semiconductor (MOS) device is an electronic component where a metallic oxide, such as silicon dioxide, acts as an insulating layer. The most crucial device for very-large-scale integrated circuits is the metal-oxide-semiconductor field-effect transistor (MOSFET).12

MOSFETs operate by using an electric field to control the conductivity of a semiconductor channel. In an n-channel MOS transistor, a positive voltage applied to the gate attracts electrons to the semiconductor surface beneath the insulating oxide layer, creating a conductive channel between the source and drain. This allows current to flow. Conversely, a negative voltage on the gate in a p-channel MOS transistor attracts holes, enabling current flow. The speed at which electrons or holes move through the semiconductor, divided by the distance between the source and drain, largely determines the operating frequency.3

MOSFETs have become dominant in integrated circuits due to their scalability, low power consumption, and simpler manufacturing processes, leading to high production yields. Combinations of n-channel and p-channel MOSFETs, known as CMOS (complementary metal-oxide-semiconductor) circuits, consume extremely little power in standby mode, making them ideal for microchips where minimizing heat generation is critical.23