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A KAIST research team developed in vivo flexible large scale integrated circuits
Daejeon, Republic of Korea, May 6th, 2013–-A team led by Professor Keon Jae Lee from the Department of Materials Science and Engineering at KAIST has developed in vivo silicon-based flexible large scale integrated circuits (LSI) for bio-medical wireless communication.
Silicon-based semiconductors have played significant roles in signal processing, nerve stimulation, memory storage, and wireless communication in implantable electronics. However, the rigid and bulky LSI chips have limited uses in in vivo devices due to incongruent contact with the curvilinear surfaces of human organs. Especially, artificial retinas recently approved by the Food and Drug Administration (refer to the press release of FDA"s artificial retina approval) require extremely flexible and slim LSI to incorporate it within the cramped area of the human eye.
Although several research teams have fabricated flexible integrated circuits (ICs, tens of interconnected transistors) on plastics, their inaccurate nano-scale alignment on plastics has restricted the demonstration of flexible nano-transistors and their large scale interconnection for in vivo LSI applications such as main process unit (MPU), high density memory and wireless communication. Professor Lee"s team previously demonstrated fully functional flexible memory using ultrathin silicon membranes (Nano Letters, Flexible Memristive Memory Array on Plastic Substrates), however, its integration level and transistor size (over micron scale) have limited functional applications for flexible consumer electronics.
Professor Keon Jae Lee"s team fabricated radio frequency integrated circuits (RFICs) interconnected with thousand nano-transistors on silicon wafer by state-of-the-art CMOS process, and then they removed the entire bottom substrate except top 100 nm active circuit layer by wet chemical etching. The flexible RF switches for wireless communication were monolithically encapsulated with biocompatible liquid crystal polymers (LCPs) for in vivo bio-medical applications. Finally, they implanted the LCP encapsulated RFICs into live rats to demonstrate the stable operation of flexible devices under in vivo circumstances.
Professor Lee said, "This work could provide an approach to flexible LSI for an ideal artificial retina system and other bio-medical devices. Moreover, the result represents an exciting technology with the strong potential to realize fully flexible consumer electronics such as application processor (AP) for mobile operating system, high-capacity memory, and wireless communication in the near future."
This result was published in the May online issue of the American Chemical Society"s journal, ACS Nano (In vivo Flexible RFICs Monolithically Encapsulated with LCP). They are currently engaged in commercializing efforts of roll-to-roll printing of flexible LSI on large area plastic substrates.
Movie at Youtube Link: Fabrication process for flexible LSI for flexible display, wearable computer and artificial retina for in vivo biomedical application
http://www.youtube.com/watch?v=5PpbM7m2PPs&feature=youtu.be
Applications of in Vivo Flexible Large Scale Integrated Circuits
Top: In vivo flexible large scale integrated circuits (LSI); Bottom: Schematic of roll-to-roll printing of flexible LSI on large area plastics.
2013.06.09 View 18165 -
KAIST develops a low-power 60 GHz radio frequency chip for mobile devices
As the capacity of handheld devices increases to accommodate a greater number of functions, these devices have more memory, larger display screens, and the ability to play higher definition video files. If the users of mobile devices, including smartphones, tablet PCs, and notebooks, want to share or transfer data on one device with that of another device, a great deal of time and effort are needed.
As a possible method for the speedy transmission of large data, researchers are studying the adoption of gigabits per second (Gbps) wireless communications operating over the 60 gigahertz (GHz) frequency band. Some commercial approaches have been introduced for full-HD video streaming from a fixed source to a display by using the 60 GHz band. But mobile applications have not been developed yet because the 60 GHz radio frequency (RF) circuit consumes hundreds of milliwatts (mW) of DC power.
Professor Chul Soon Park from the Department of Electrical Engineering at the Korea Advanced Institute of Science and Technology (KAIST) and his research team recently developed a low-power version of the 60 GHz radio frequency integrated circuit (RFIC). Inside the circuit are an energy-efficient modulator performing amplification as well as modulation and a sensitivity-improved receiver employing a gain boosting demodulator.
The research team said that their RFIC draws as little as 67 mW of power in the 60 GHz frequency band, consuming 31mW to send and 36mW to receive large volumes of data. RFIC is also small enough to be mounted on smartphones or notebooks, requiring only one chip (its width, length, and height are about 1 mm) and one antenna (4x5x1 mm3) for sending and receiving data with an integrated switch.
Professor Park, Director of the Intelligent Radio Engineering Center at KAIST, gave an upbeat assessment of the potential of RFIC for future applications. What we have developed is a low-power 60-GHz RF chip with a transmission speed of 10.7 gigabits per second. In tests, we were able to stream uncompressed full-HD videos from a smartphone or notebook to a display without a cable connection (Youtube Link: http://www.youtube.com/watch?v=6PVSLBhMymc). Our chip can be installed on mobile devices or even on cameras so that the devices are virtually connected to other devices and able to exchange large data with each other."
2013.04.02 View 11256