A research group led by Associate Professor Soo Shimizu of Tokyo Institute of Technology, Professor Hiroshi Funakubo of the same university, and Professor Toyohiko Konno of Tohoku University has succeeded in producing an ultrathin film of ferroelectrics with stable quality.Ferroelectrics are currently attracting attention as a high-performance new memory material that replaces the memory used in smartphones and the like.
It is indispensable to make an ultra-thin film in order to realize it, but there was a problem that it deteriorated as the film became thinner.The state of the memory changes when a voltage is applied, and information is held by a substance that maintains that state even when the voltage is turned off.Ferroelectrics achieve this by applying a voltage that biases the distribution of ions in the substance.It is said that it can achieve high performance and low power consumption compared to conventional memory.On the other hand, there are still issues, and it is indispensable to produce thin film-like crystals of particularly stable quality.
What we paid attention to was hafnium oxide, a ferroelectric substance, which has the characteristic of a reverse size effect whose characteristics improve as the size decreases.On the other hand, the difficulty in producing stable crystals was a bottleneck.The research group first reexamined the composition of the elements contained in the crystal.Furthermore, by devising the structure of the base on which the crystal grows, we succeeded in producing a crystal with a thickness of 15 nm (100 millionth of a millimeter) and stable quality.
It is said that by using this ferroelectric thin film, it is possible to realize a memory with a larger capacity, lower power consumption, and higher speed than the conventional memory.If implemented on smartphones and laptops, we will be able to benefit directly.In addition, the mechanism of the reverse size effect has not yet been clarified, and the crystal created this time may be a clue to its elucidation.If it can be clarified, the development of new substances will be further accelerated.
