- About Us
- Career Center
- Nano-Social Network
- Nano Consulting
- My Account
A new approach to integrated circuits, combining atoms of semiconductor materials into nanowires and structures on top of silicon surfaces, shows promise for a new generation of fast, robust electronic and photonic devices. Engineers at the University of California, Davis, have recently demonstrated three-dimensional nanowire transistors using this approach that open exciting opportunities for integrating other semiconductors, such as gallium nitride, on silicon substrates.
Nanowires Grown on Silicon
"Silicon can't do everything," said Saif Islam, professor of electrical and computer engineering at UC Davis. Circuits built on conventionally etched silicon have reached their lower size limit, which restricts operation speed and integration density. Additionally, conventional silicon circuits cannot function at temperatures above 250 degrees Celsius (about 480 degrees Fahrenheit), or handle high power or voltages, or optical applications.
The new technology could be used, for example, to build sensors that can operate under high temperatures, for example inside aircraft engines.
"In the foreseeable future, society will be dependent on a variety of sensors and control systems that operate in extreme environments, such as motor vehicles, boats, airplanes, terrestrial oil and ore extraction, rockets, spacecraft, and bodily implants," Islam said.
Devices that include both silicon and nonsilicon materials offer higher speeds and more robust performance. Conventional microcircuits are formed from etched layers of silicon and insulators, but it's difficult to grow nonsilicon materials as layers over silicon because of incompatibilities in crystal structure (or "lattice mismatch") and differences in thermal properties.
Instead, Islam's laboratory at UC Davis has created silicon wafers with "nanopillars" of materials such as gallium arsenide, gallium nitride or indium phosphide on them, and grown tiny nanowire "bridges" between nanopillars.
"We can't grow films of these other materials on silicon, but we can grow them as nanowires," Islam said.
The researchers have been able to make these nanowires operate as transistors, and combine them into more complex circuits as well as devices that are responsive to light. They have developed techniques to control the number of nanowires, their physical characteristics and consistency.
Islam said the suspended structures have other advantages: They are easier to cool and handle thermal expansion better than planar structures — a relevant issue when mismatched materials are combined in a transistor.
The technology also leverages the well-established technology for manufacturing silicon integrated circuits, instead of having to create an entirely new route for manufacturing and distribution, Islam said.
The work is described in a series of recent papers in the journals Advanced Materials, Applied Physics Letters and IEEE Transactions on Nanotechnology with co-authors Jin Yong Oh at UC Davis; Jong-Tae Park, University of Incheon, South Korea; Hyun-June Jang and Won-Ju Cho, Kwangwoon University, South Korea. Funding was provided by the U.S. National Science Foundation and the government of South Korea.
About University of California - Davis
UC Davis is a global community of individuals united to better humanity and our natural world while seeking solutions to some of our most pressing challenges. Located near the California state capital, UC Davis has more than 34,000 students, and the full-time equivalent of 4,100 faculty and other academics and 17,400 staff. The campus has an annual research budget of over $750 million, a comprehensive health system and about two dozen specialized research centers. The university offers interdisciplinary graduate study and 99 undergraduate majors in four colleges and six professional schools.
For more information, please click here
Electrical and Computer Engineering
Copyright © University of California - DavisIf you have a comment, please Contact us.
Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
|Related News Press|
News and information
The quantum middle man July 2nd, 2015
Emergence of a 'devil's staircase' in a spin-valve system July 1st, 2015
Exagan Raises €5.7 Million to Produce High-efficiency GaN-on-Silicon Power-switching Devices on 200mm Wafers: Leti-and-Soitec Spinout Focused on Becoming Leading European Source Of GaN Devices for Solar, Automotive, Telecoms and Infrastructure June 25th, 2015
Nanowires could be the LEDs of the future June 25th, 2015
Leti to Present Solutions to New Applications Using 3D Technologies at SEMICON West LetiDay Event, July 14: Leti Experts also Will Speak at TechXPOT Session on MEMS and STS Session on Lithography Cost-and-Productivity Issues Below 14nm June 22nd, 2015
Producing spin-entangled electrons July 2nd, 2015
Leti Announces Launch of First European Nanomedicine Characterisation Laboratory: Project Combines Expertise of 9 Partners in 8 Countries to Foster Nanomedicine Innovation and Facilitate Regulatory Approval July 1st, 2015