Intel Invents New 3 Dimensional Transistor for 22nm Ivy Bridge CPUs, Dubs it "Tri-Gate"
Subject: General Tech, Processors | May 4, 2011 - 05:55 PM | Tim Verry
Tagged: transistor, Intel
"After a decade of research, Intel has unveiled the world's first three dimensional transistor" states Mark Bohr, a Senior Fellow for Intel. Silicon based transistors in computers, mobile devices, vehicles, and embedded equipment have only existed in a planar, or two dimensional, form until today.
The new three dimensional transistor, dubbed "Tri-Gate," is now ready for high volume production, and will be included in Intel's new Ivy Bridge 22nm processors. This new Tri-Gate transistor is a huge deal for Intel as it will enable them to maintain the pace of current chip evolution as outlined by Moore's Law. If you are not familiar with Moore's Law, it states that approximately every 18 months, transistor density will double, bringing with it increases in performance and yeild while decreasing cost of production. Intel states that "It has become the basic business model for the semiconductor industry for more than 40 years."
As processors become smaller and smaller, the electric current becomes more and more difficult to contain. There are hundreds of thousands of minute connections and switches inside today's processors, and as manufacturing processes shrink, the amount of current leakage increases. With Intel's Core 2 Duo processors, Intel created a new "high-k"(high dielectric constant, which is a property of matter relating to the amount of charge it can hold) metal gate transistor using a material called Hafnium. The new material replaced the silicon dioxide dielectric gate of the transistor to combat the current leakage problem at 32nm. This allowed the chip process to shrink while scaling to produce less current leakage and heat. To be more specific, Intel states that "because high-k gate dielectrics can be several times thicker, they reduce gate leakage by over 100 times. As a result, these devices run cooler."
Unfortunately, at the much smaller 22nm process, Intel was not achieving results congruent with Moore's Law using even their high-k gate transistors. In order to maintain the scaling predicted in Moore's Law, Intel had to once again re-invent their transistors. In order to create a smaller manufacturing process while overcoming current leakage, Intel had to develop a way to use more of what little space they had available to them. It is here that they entered the third dimension. By designing a transistor that is able to control the electrical current on three sides instead of a single plane, they are able to shrink the transistor while ending up with more surface area to "control the stream" as Mark Bohr puts it.
The proposed benefits of Tri-Gate lie in it's ability to operate at lower voltages, with higher energy efficiency, all while running cooler and faster than ever before. More specifically, up to 37 percent increases in performance at low voltages versus Intel's current line of 32nm processors. Intel further states that "the new transistors consume less than half the power when at the same performance as 2-D planar transistors on 32nm chips." This means that at the same performance level of the current crop of Intel CPUs, Ivy Bridge will be able to do the same calculations either while using half the power needed of Sandy Bridge or nearly twice as fast (it is unlikely to scale perfectly as there is overhead and other elements of the chip that will not be as radically revamped) at the same level of power consumption. If this sort of scaling turns out to be true for the majority of Ivy Bridge chips, the overclocking abilities and resulting performance should be of unprecedented levels.
The use of Tri-Gate transistors is also mentioned as being beneficial for mobile and handheld devices as the power efficiency should allow increases in battery life. This is due to the chip running at decreased voltages while maintaining (at least) the same level of performance as current mobile chips. While Intel did not demo any mobile CPUs, they did state that Tri-Gate transistors may be integrated into future Atom chips.