[Keio Spintronics Network - Nano-Spin Laboratory, Research Institute of Electrical Communication, Tohoku University]
A group led by Professor Hideo Ohno in the Laboratory of Nanoelectronics and Spintronics, at Tohoku Universitys Research Institute of Electrical Communication, is working to develop new integrated circuits using spintronics, which combines magnets and semiconductors.
The core of a modern computer consists of integrated circuits, which have billions of transistors on a silicon chip just a few mm square. Transistors are switching elements, operated by electrical charge. So far, technology for making these circuits smaller has been advancing, but in the near future, it will reach its limit. Hideo Ohnos group hopes to overcome this limit by using spintronics technology.
Q. In integrated circuits, you cant just arrange things side by side; you have to consider how components should be connected to give certain functions. Luckily for us, we had our colleague Prof. Takahiro Hanyu close at hand, so we were able to discuss an interesting new approach to integrated circuits, and expand our research network in the process.
Q. Todays integrated circuits have been successfully achieved using semiconductors. But power consumption is a big issue. For example, one chip may consume 120 W, with over 100 W being required within a few square mm. So chip development is becoming unsustainable in terms of power density. Therefore, wed like to bring together materials that free us from dependence on silicon. Japan is very strong in nano-technology, so wed like to solve the power consumption problem by combining new materials with nano-technology.
Integrated circuits using the spintronics being developed by Ohnos group store data in nonvolatile memory using magnetism, so their standby power can be made zero. This memory utilizes the tunnel magneto-resistance effect, which is being studied by Shoji Ikedas group, who also do joint research with Ohnos group.
Q. This is the same technology as that used in hard disk heads, but by using it for memory and logic, we obtain memory and logic where the power can be turned off when theyre not running. This is nonvolatile memory, which uses magnets, so their direction doesnt change if the power is turned off.
Were working on a government project led by Prof. Ohno, which involves research and development with a number of companies. Regarding the memory I mentioned earlier, were doing a project with Hitachi. Currently, were fabricating a prototype 32 Mbit memory using magneto-resistance.
Tunnel magneto-resistance elements are being co-developed with Hitachi. These have achieved the worlds highest magneto-resistance ratio of 604%, much higher than that attained previously at room temperature. This technology has been used to successfully fabricate a nonvolatile logic-in-memory circuit, where the memory layer and logic layer are connected by magnetic tunnel elements. The basic operation of this device has also been demonstrated in a world-first achievement. This is a major step toward achieving integrated circuits that combine high speed and low power consumption, which has been considered difficult so far.
Q. We think that, if a worldwide market can be opened up through our R&D, this could be developed into an industry in many significant ways. The topic thats most directly relevant currently is how to make devices more energy-efficient. I think that making the cores of devices more energy-efficient is the aspect of our research most closely related to daily life at present.
Under Hideo Ohnos leadership, collaboration among researchers with a diverse range of knowledge and experience has led to integrated circuits using spintronics technology. The group will continue its R&D, with the aim of making these devices perform even better.
Негізгі бет Ғылым және технология high-speed, ultra low-power integrated circuits using non-volatile logic-in-memory
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