Tri-Gate Transistor

Transistors are the microscopic, silicon-based switches that process the ones and zeros of the digital worlds and are the fundamental building block of all semiconductor chips. With traditional planar transistors, electronic signals travel as if on a flat, one-way road. This approach has served the semiconductor industry well since the 1960s. But, as transistors shrink to less than 30 nanometers (billionths of a meter), the increase in current leakage means that transistors require increasingly more power to function correctly, which generates unacceptable levels of heat.

Intel's tri-gate transistor employs a novel 3-D structure, like a raised, flat plateau with vertical sides, which allows electronic signals to be sent along the top of the transistor and along both vertical sidewalls as well. This effectively triples the area available for electrical signals to travel, like turning a one-lane road into a three-lane highway, but without taking up more space. Besides operating more efficiently at nanometer-sized geometries, the tri-gate transistor runs faster, delivering 20 percent more drive current than a planar design of comparable gate size.

The tri-gate structure is a promising approach for extending the TeraHertz transistor architecture Intel announced in December 2001. The tri-gate is built on an ultra-thin layer of fully depleted silicon for reduced current leakage. This allows the transistor to turn on and off faster, while dramatically reducing power consumption. It also incorporates a raised source and drain structure for low resistance, which allows the transistor to be driven with less power. The design is also compatible with the future introduction of a high K gate dielectric for even lower leakage.
Intel researchers have developed "tri-gate" transistor design. This is one of the major breakthroughs in the VLSI technology. The transistor is aimed at bringing down the transistor size in accordance with the Moore’s Law. The various problems transistors with very small size face have to be overcome. A reduction in power dissipation is another aim. This is to develop low power micro processors and flash memories.

Tri-gate transistors show excellent DIBL, high sub threshold slope, high drive and much better short channel performance compared to CMOS bulk transistor. The drive current is almost increased by 30%. The thickness requirement of the Si layer is also relaxed by about 2-3 times that of a CMOS bulk transistor.
Tri- gate transistors are expected to replace the nanometer transistors in the Intel microprocessors by 2010. 60 nm tri-gate transistors are already fabricated and 40 nm tri-gate transistors are under fabrication. Tri-gate transistor is going to play an important role in decreasing the power requirements of the future processors. It will also help to increase the battery life of the mobile devices.