Intel Announces Breakthrough In Chip Transistor Design
New type of transistor and new materials combine to address critical power issues and help chips run cooler
SANTA CLARA, Calif., Nov. 26, 2001 -- Intel Corporation today announced that its researchers have developed an innovative transistor structure and new materials that represent a dramatic improvement in transistor speed, power efficiency and heat reduction. The technology development is an important milestone in the effort to maintain the pace of Moore's Law and remove the technical barriers that Intel and the semiconductor industry have only recently begun to identify.
The technology breakthrough, coupled with recent announcements from Intel on faster and smaller transistors, will enable powerful new applications such as real-time voice and face recognition, computing without keyboards, and smaller computing devices with higher performance and improved battery life.
"Our research has shown that we can continue to make smaller and faster transistors, but there are fundamental problems we need to address around power consumption, heat generation, and current leakage," said Gerald Marcyk, director of components research, Intel Labs. "Our goal is to overcome these barriers and produce chips that have 25 times the number of transistors of today's microprocessors at ten times the speed with no increase in power consumption."
Intel researchers will discuss two major elements of the new transistor structure at the International Electron Device Meeting (IEDM) in Washington D.C. on Dec. 3. Intel's technical papers will address power consumption, current leakage, and heat issues with two significant improvements to existing transistor design: a new type of transistor called a "depleted substrate transistor" and a new material called a "high k gate dielectric." Together, these advancements dramatically reduce current leakage and power consumption.
Power consumption as a limiting factor
As semiconductors become more complex and new milestones in transistor size and performance are achieved, power consumption and heat have recently emerged as limiting factors to the continued pace of chip design and manufacturing. Applying existing designs to future processors becomes unworkable because of current leakage in the transistor structure, which in turn requires more power and generates more heat. Transistors are the microscopic, silicon-based switches that process the ones and zeros of the digital world.
Intel has already developed the world's smallest and fastest CMOS transistors, including a 15 nanometer transistor, which will enable chips with up to one billion transistors by the second half of this decade. However, as hundreds of millions, and even billions of smaller and faster transistors get packed on to a single piece of silicon the size of a thumbnail, power consumption and the amount of heat generated in the processor core becomes a significant technical challenge. Using existing methods of semiconductor design would eventually lead to chips that are simply too hot for desktop computers and servers. These limitations could even prevent new chip designs from being implemented in smaller computers like mobile PC's and handheld devices.
"Smaller and faster just isn't good enough anymore," Marcyk said. "Power and heat are the biggest issues for this decade. What we are doing with our new transistor structure is helping
make devices that are extremely power efficient, concentrating electrical current where it's needed."
The new structure is being called the Intel TeraHertz transistor because the transistors will be able to switch on and off more than one trillion times per second. In comparison, it would take a person more than 15,000 years to turn a light switch on and off a trillion times.
Depleted substrate transistor
One element of the new structure is a "depleted substrate transistor," which is a new type of CMOS device where the transistor is built in an ultra-thin layer of silicon on top of an embedded layer of insulation. This ultra-thin silicon layer, which is different than conventional silicon-on-insulator devices, is fully depleted to create maximum drive current when the transistor is turned on, enabling the transistor to switch on and off faster.
In contrast, when the transistor is turned off, unwanted current leakage is reduced to a minimum level by the thin insulating layer. This allows the depleted substrate transistor to have 100 times less leakage than traditional silicon-on-insulator schemes. Another innovation of Intel's depleted substrate transistor is the incorporation of low resistance contacts on top of the silicon layer. The transistor can therefore be very small, very fast and consume less power.
New material replaces silicon dioxide
Another key element is the development of a new material that replaces silicon dioxide on the wafer. All transistors have a "gate-dielectric," a material that separates a transistor's "gate" from its active region (the gate controls the on-off state of the transistor). The record-setting transistors introduced in the past year had gate dielectrics made of silicon dioxide that are only 0.8 nanometers, or approximately three atomic layers thick. However, the leakage through this atomically thin insulator layer is becoming one of the largest sources of power consumption of chips.
At the IEDM conference, Intel researchers will demonstrate record speed for transistors made with a new type of material called a "high k gate dielectric." This new material reduces gate leakage by more than 10,000 times compared to silicon dioxide. The high k gate material is grown by a revolutionary technology called "atomic layer deposition" in which the new material can be grown in layers only one molecule thick at a time. The result is higher performance, reduction of heat, and significantly longer battery life for mobile applications.
The Intel TeraHertz transistor solves a key barrier to bringing future chips into volume production that enable a whole new range of applications. Intel is expected to begin incorporating elements of this new structure into its product line as early as 2005.
For more information on the TeraHertz transistor and other silicon research at Intel, visit Intel's Silicon Showcase at www.intel.com/research/silicon.