Self-aligned gate

In electronics, a self-aligned gate is a transistor manufacturing feature whereby a refractory gate electrode region of a MOSFET transistor is used as a mask for the doping of the source and drain regions. This technique ensures that the gate will slightly overlap the edges of the source and drain.

The use of self-aligned gates is one of the many innovations that led to the large increase in computing power in the 1970s. Self-aligned gates are still used in most modern integrated circuit processes.

Introduction

The self-aligned gate is used to eliminate the need to align the gate electrode to the source and drain regions of a MOS transistor during the fabrication process. With self-aligned gates the parasitic overlap capacitances between gate and source, and gate and drain are substantially reduced, leading to MOS transistors that are faster, smaller and more reliable than transistors made without them. After the early experimentation with different gate materials (aluminum, molybdenum, amorphous silicon) the industry almost universally adopted self-aligned gates made with polycrystalline silicon, the so-called Silicon Gate Technology (SGT), which had many additional benefits over the reduction of parasitic capacitances. One important feature of SGT was that the silicon gate was entirely buried under top quality thermal oxide (one of the best insulators known), making it possible to create new device types, not feasible with conventional technology or with self-aligned gates made with other materials. Particularly important are charge coupled devices (CCD), used for image sensors, and non-volatile memory devices using floating silicon-gate structures. These devices dramatically enlarged the range of functionality that could be achieved with solid state electronics.

Gate

A gate or gateway is a point of entry to a space enclosed by walls, or a moderately sized opening in some sort of fence. Gates may prevent or control the entry or exit of individuals, or they may be merely decorative. Other terms for gate include yett and port. The word derives from the old Norse "gata", meaning road or path, and originally referred to the gap in the wall or fence, rather than the barrier which closed it. The moving part or parts of a gateway may be called "doors", but used for the whole point of entry door usually refers to the entry to a building, or an internal opening between different rooms.

A gate may have a latch to keep it from swinging and a lock for security. Larger gates can be used for a whole building, such as a castle or fortified town, or the actual doors that block entry through the gatehouse. Today, many gate doors are opened by an automated gate operator.

Types

Types of gates include:

List of scandals with "-gate" suffix

This is a list of scandals or controversies whose names in scholarly sources include a "-gate" suffix, by analogy with the Watergate scandal. This list also includes controversies that are widely referred to with a "-gate" suffix, but may be referred to by another more common name in scholarly sources (such as New Orleans Saints bounty scandal).

Etymology, usage, and history of -gate

The suffix -gate derives from the Watergate scandal of the United States in the early 1970s, which resulted in the resignation of U.S. President Richard Nixon. The scandal was named after the Watergate complex in Washington, D.C.; the complex itself was named after the "Water Gate" area where symphony orchestra concerts were staged on the Potomac River between 1935 and 1965.

The suffix is used to embellish a noun or name to suggest the existence of a far-reaching scandal, particularly in politics and government. As a CBC News column noted in 2001, the term may "suggest unethical behaviour and a cover-up". The same usage has spread into languages other than English; examples of -gate being used to refer to local political scandals have been reported from Argentina, Germany, Korea, Hungary, Greece and the former Yugoslavia.

Gate (disambiguation)

A gate is an opening in a wall or fence fitted with a moveable barrier allowing it to be closed.

Gate or GATE may also refer to:

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