HOME > Organization / Research > Cho Laboratory

Organization / Research

Cho Laboratory


photo Yasuo CHO, Professor
Kohei YAMASUE, Associate Professor
Yoshiomi HIRANAGA, Assistant Professor

Our main area of interest is evaluation and development of dielectric materials, including ferroelectric and piezoelectric materials and their application to communication devices and ferroelectric data storage systems.

Our measure contributions to advancement in these fields are the invention and the development of “Scanning Nonlinear Dielectric Microscope” (SNDM) which is the first successful purely electrical method for observing the ferroelectric polarization distribution without the influence of the shielding effect by free charges and it has already been put into practical use. The resolution of the microscope has been improved up to atomic scale-order. Therefore, it has a great potential for realizing the ultra-high density ferroelectric recording system. Our recent research achieved to fabricate an ultra-small domain inversion dot, which has the diameter of 3 nm in case of single dot fabrication, and achieved the recording density of 4 Tbit/inch2 in actual information storage, requiring an abundance of bits to be packed together.(Fig.3)

Moreover, we have started to make a measurement and an evaluation of flash-memory device and dopant profile in semiconductor devices using SNDM. Because SNDM can detect very small capacitance variation, it can be a very powerful evaluation tool for various materials. Now SNDM evolves into a new evaluation technique for insulator material and semiconductor materials besides ferroelectric materials.

Research topics:

  1. Development of scanning nonlinear dielectric microscope (SNDM) with super high (atomic-scale) resolution.
  2. Ultra-high density ferroelectric recording system using SNDM.
  3. Development of ferroelectric functional devices for electrical communications using nano-domain engineering based on SNDM.
  4. Evaluation of ferroelectric material and piezoelectric material using SNDM.
  5. Evaluation of flash-memory device and dopant profile in semiconductor devices using SNDM.
Group of Electrical Engineering, Communication Engineering,
Electronic Engineering, and Information Engineering, Tohoku University
6-6-05, Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi 980-8579, Japan
TEL : 022-795-7186 (Japanese Only)
Email :