Component | Materials
Printing Method Fabricates Organic Semiconductor Wafers
The new discovery paves the way for mass production of high-performance transistors for IoT devices.

U

sing a simple printing method, a research group has fabricated wafers of organic semiconductors that can be used as high-performance transistors. The group consisted of the Graduate School of Frontier Sciences and Material Innovation Research Center, The University of Tokyo, AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory, National Institute for Materials Science, and Pi-Crystal, Inc.

Due to their lightness, flexibility, printing compatibility, organic semiconductors have been expected as next-generation electronic materials that can be mass produced at low cost and replace silicon semiconductors. Therefore, organic semiconductors suitable for actual devices and printing methods for fabrication have been developed for a long time.

Fabricated Transistors Without Defects
The research group has demonstrated that a four-inch wafer of an ultrathin organic semiconductor single-crystal film with thickness of about three layers of molecules can be produced by using original organic semiconductor materials and printing technology. It has been demonstrated that 1,600 transistors fabricated on this single wafer operate without defects, and the average carrier mobility exceeds 10cm2/Vsec (square centimeter per volt per second), which is a reference value for practical use.

The developed printing method consumes much less quantity of materials in comparison with the conventional method of organic semiconductor printing. In addition, the process requires shorter time relative to other methods when the printing area is increased. A significant cost reduction is therefore expected in future industrial applications.

In the future, the development of higher-performance organic semiconductor materials and printing equipment will be promoted, aiming at the establishment of much large area printing technology, including introduction of a roll-to-roll printing method. At the same time, Pi-Crystal is developing high-performance integrated circuits using the printing technology and will commercialize them soon.

The present achievement is expected to promote the development of internet of Things (IoT) devices that can be mass produced at low cost.