During the international IEDM 2016 conference, Purdue University researchers showcased a range of concepts and technologies that foreshadow the future of the semiconductor industry. The concepts included innovations to extend the performance of today’s silicon-based transistors, and new types of nano-electronic devices to complement and replace conventional technology in future computers.
Image source: Purdue University.
According to professor of electrical and computer engineering and director of Purdue's Network for Computational Nanotechnology, Gerhard Klimeck, electronic device innovation has been a major economic factor in the U.S. and world economy. “These advancements were enabled by making the basic transistors in computer chips ever smaller,” Klimeck said. “Today the critical dimensions in these devices are just some 60 atoms thick, and further device size reductions will certainly stop at small atomic dimensions.”
Of course, new technologies will be needed for the industry to keep pace with Moore's law, an observation that the number of transistors on a computer chip doubles nearly every two years, resulting in rapid progress in computers and telecommunications. It’s becoming increasingly difficult to continue shrinking electronic devices made of conventional silicon-based semiconductors, according to professor of electrical and computer engineering, Muhammad Ashraful Alam.
Integrated circuits, also known as chips, currently contain around two billion transistors. The more devices that are packed onto a chip, the greater the heating. Today's chips generate about 100 watts per square centimeter, comparable to that of a nuclear reactor.
“As a result, self-heating has become a fundamental concern that hinders performance and can damage transistors, and we are making advances to address it,” Alam said.
Two of the five papers presented by Purdue at IEDM detail research to suppress self-heating and enhance the performance of conventional CMOS chips. The other papers deal with new devices for future computer technologies that require lower power to operate, meaning they would not self-heat as significantly.
“We are not only working to extend the state-of-art of traditional technology, but also to develop next-generation transistor technologies,” Alam said.
Transistors are electronic switches that turn on and off to allow computations using the binary code of ones and zeros. A critical component in transistors, called the gate, controls this switching. But, as progressively smaller transistors are designed, this control becomes increasingly difficult because electrons leak around the ultra-small gate.
One of the conference papers prepared by the researchers focuses on a potential solution to this leakage: creating transistors that are surrounded by the gate, instead of a customary flat design. But unfortunately, surrounding the transistor with a gate causes increased heating, hindering reliability and damaging the device. The researchers used a technique called submicron thermo-reflectance imaging to pinpoint locations of excessive heating. Another paper describes a potential approach to suppress this self-heating, modeling how to effectively dissipate heat by changing how the transistor connects to the complex circuitry in the chip.
As for the three remaining papers, they propose next-generation devices: networks of nano-magnets, thin layers of a material called black phosphorous, and “tunnel” field effect transistors, or FETs. Technologies such as these would operate at far lower voltages than existing electronics, generating less heat. The tunnel FETS could potentially reduce power consumption by more than 40 times.
One of the conference papers details research to develop devices made of black phosphorous, which may one day replace silicon as a semiconductor in transistors. According to the team, future research will include efforts to create smaller black phosphorous devices.
A fifth paper describes how networks of nano-magnets could serve as the building blocks of future computers. The networks mimic Ising networks — named after German physicist Ernst Ising — which harness mathematics to solve complex problems.
Source: Purdue University, TechXplore
Advertisement
Learn more about Electronic Products Magazine
