Site: Radioengineering Institute
P. Brovki str. 6
Date Visited: October 27, 1993
Report Author: Z. Yaniv
Dr. Alexander G. Smirnov
Dr. Andrei B. Usenok
The AMLCD activity of Dr. Alexander Smirnov's group at the Radioengineering Institute started in 1986 using a-Si TFTs. The group obtained very low off-current (10-12 A) and more than one micro amp of on-current. The threshold was high (Vth = 8 V) due to poor dielectric properties. No mobility information was available. In 1988, the scientists showed a 160 x 128 display using both TFTs and MIMs.
In 1989, they decided to concentrate their efforts on MIMs due to the development of very high resistivity liquid crystals at the Belarus Institute of Applied Physics. In 1989 they demonstrated a 320 x 200 color television using MIM with CR 15:1, video signal ñ3 V, and driving voltages ñ15 V. Today the demonstrator is 6" þ 640 x 400.
The Radioengineering Institute's research and development efforts emphasize improving the yield of 6" þ MIMs in collaboration with Integral. The group has a two-room laboratory with some five to seven people, including students. The equipment is rudimentary, but the interesting collaboration with Integral gives fruit. Each student works four or more hours a day at Integral as a line manager, where he or she implements the results of the R&D discussed or discovered in the department. Generally, for the MIM the students use usual glass passivated with Ta2O5. Their MIM is using a Ta- Ta2O5--Cr structure that shows a more symmetric IV curve than Ta-Ta2O5--ITO. Redundancy is executed using two MIMs per pixel. The MIM capacity is controlled by a similar lateral structure as Seiko- Epson. The spacers are formed by etching the glass. Furthermore, the fitting of the cell gap for each color pixel is also done by etching the glass substrates.
The Smirnov group is interested in collaboration. At the time of the WTEC team's visit, the group's scientists were particularly in need of TI gray-scale drivers because Integral developed only binary drivers; gray-scale drivers were scheduled to be available eighteen months after the WTEC visit. In addition, they developed a PDLC display on Si wafers in reflections for projection applications.
The Smirnov group of the Radioengineering Institute is the brain behind the AMLCD activities in Belarus. Presently the laboratory, although poorly equipped, has some good scientists that by working in conjunction with Integral, Belarus University, and Planar, could give excellent results.
The hosts provided the site report author with brochures and other documentation on the background of the institute; the MIM color TV demonstrator and MIM research at the institute; and a list of publications. Further information on these documents is available from the author on request.