Semiconductor Energy Laboratory Co., Ltd.

SEL discovered a crystal structure with c-axis alignment in a direction perpendicular to the film surface and without alignment in the a-b plane (CAAC^®), in a crystalline oxide semiconductor thin film formed at temperatures lower than 450℃. This is a completely novel crystal structure that differs from single crystals, which do not have distortions, as well as from polycrystals, which have clear grain boundaries.

Feature of CAAC structure

IGZO Single Crystal Structure

Miniaturized CAAC-OS FET

SEL has succeeded in fabricating a miniaturized CAAC-OS FET with a gate length of 13 nm (a CAAC-OS island width of 26 nm) applicable to LSI and achieved a cutoff frequency of 60 GHz^[4] for the first time in the world.



In addition to the CAAC-OS, we have discovered a crystal structure called nc-OS^®and expanded the use of crystalline oxide semiconductors in a wide range of applications including the LSI field and the display field. For more detailed information on the CAAC-OS, please refer to the book "Physics and Technology of Crystalline Oxide Semiconductor CAAC-IGZO."

[4] Reprinted with permission from A. Suzuki et al., ECS Trans, vol. 98, No. 7, p. 13-27 (2020) Copyright 2020, The Electrochemical Society