Professor, Research Institute of Electronics

Shizuoka University, Japan

Title : SOI photodiode with surface plasmon antenna: from sensitivity enhancement to refractive index measurement for biosensing

Abstract

In order to enhance the performance and functionality of the pn-junction photodiode in silicon on insulator (SOI), metallic line-and-space (L/S) surface plasmon (SP) antenna is introduced. In case of the 100-nm-thick silicon, external quantum efficiency (QE) of the photodiode can be increased by nearly an order of magnitude. The antenna shows wavelength and polarization selectivities, and incident angle dependence, and the peak wavelength and the polarization angle can be tailored only by changing the layout design. This is especially beneficial for integrating a variety of photodiodes with different characteristics in a single chip.

Wavelengths of the QE peaks for various L/S pitches and light incident angles were examined in detail, and it was suggested that the coupling between the diffracted light from the L/S and the propagation modes in the SOI slab waveguide caused the QE enhancement.

Related to this operation mechanism, it was found that the photodiode could detect the refractive index of the medium around the SP antenna as the shift of the peak wavelength when the incident light was tilted. This may lead to the fluorescence-label-free biosensing, featuring simple optics and high throughput attained by the parallelism with a large number of integrated photodiodes.

Consequently, a wider application of this photodiode can be expected along with the evolution of the SOI-based large-scale integrated circuits (LSIs).

Biography

Prof. Dr. Hiroshi Inokawa received Ph.D. degree in electrical engineering from Kyoto University, Japan in 1985. In the same year, he joined the Atsugi Electrical Communications Laboratories, Nippon Telegraph and Telephone Corporation (NTT), Kanagawa, Japan. Since then, he has been engaged in the research and development of scaled-down CMOS devices and silicon single-electron devices. During the course of his research, he invented the basic structure of FinFET in 1989 and single-electron multiple-valued logic in 2001, and received IEEE International Symposium on Multiple-Valued Logic (ISMVL) Outstanding Contributed Paper Awards in 2004 and 2006, Director's Award of NTT Basic Research Laboratories in 2004, 28th JSAP Award for the Best Original Paper in 2006, etc. In 2006, he became a professor of the Research Institute of Electronics, Shizuoka University, Hamamatsu, Japan, where he has been studying nanodevices for advanced circuits and systems. His recent work on SOI MOSFET single-photon detector was introduced by IEEE Photonics Journal in 2012 as a Breakthrough in Photonics.

Prof. Inokawa is a member of the Institute of Electrical and Electronics Engineers (IEEE), the Japan Society of Applied Physics (JSAP), the Institute of Electronics, Information and Communication Engineers of Japan (IEICE), and the Institute of Electrical Engineers of Japan (IEEJ). He has served as a JSAP board member of representative in 2001-2003, an editor of JJAP in 2007-2013, the chair of the IEEJ survey committee of silicon nanosystem integration technology in 2009-2011, an advisory committee member of NICT Japan Trust International Research Cooperation Program in 2006-2009, a researcher of National Institute of Science and Technology Policy (NISTEP) in 2002-present, etc.