Optical probing of ultrafast devices and integrated circuits

Abstract

Rapid progress in the speed of semiconductor devices and integrated circuits has been creating a great need for new characterization and testing methods capable of subpicosecond temporal and/or submicrometre spatial resolution. In the past ten years, ultrafast lasers, optoelectronics and microfabrication technologies have spawned a variety of novel and practical measurement techniques to meet this demand, and some of them have been evolving toward commercial instruments. This special issue emphasizes recent advances in optical probing techniques and their application to high-speed electronic-optoelectronic devices and integrated circuits. The present issue offers six invited papers and twelve regular papers. All the invited papers are review articles covering the active research and development in this vital area. The first invited paper provides an overview of basic issues with respect to signal generation, propagation and detection. Among the detection techniques, electrooptic sampling has become a standard for high-frequency measurements because of its unprecedented temporal resolution. The second invited paper describes the theoretical aspect of electrooptic sampling based on state-of-the-art full-wave electromagnetic simulation. As the most important and unique applications of electrooptic sampling, the third and fourth papers, respectively, present a device network analysis and two-dimensional field mapping of monolithic microwave integrated circuits (MMICs). The final two invited papers, respectively, focus on submicrometre-spatialresolution techniques based on scanning force microscopy combined with pure-electronic and optoelectronic technologies. The seven papers selected from regular contributions feature various applications of electrooptic sampling: characterization of leading-edge devices, such as field-effect transistors and resonant tunnelling diodes, diagnosis of MMICs by two-dimensional field mapping, sampling oscilloscope calibration, and terahertz-field measurement in space. Two of these papers describe important practical issues: the improvement of accuracy in time-domain network analysis, and enhancement of sensitivity in photoconductive sampling. The final three regular papers address fundamental concepts and application of laser-diode-based optical signal sources and electrical signal generators. I would like to thank all the authors for their enthusiastic submissions to this issue, and also express my deepest appreciation to the referees who have contributed to the success of this issue through their dedicated efforts in reviewing the manuscripts. Finally, I am most grateful to the journal editor, Professor Alan Miller, for his kind support from planning to publication.