Researchers at University of Tsukuba have developed an ultrafast time-resolved scanning electron microscopy instrument by integrating a scanning electron microscope with a femtosecond laser. This innovative system faciliates the observation of the instantaneous states of various materials. Using the improved instrument, they have successfully visualized potential changes around a metal electrode on a GaAs substrate with a temporal resolution of 43 picoseconds.

Tsukuba, Japan—The rapid advancement of electronic devices, which underpins modern society, demands increasingly faster operating speeds. Active research and development efforts are directed towards the next generation of technologies that surpass today's fastest 5G band, known as Beyond 5G. To facilitate the development of these ultrafast semiconductor devices, precise measurement of high-speed phenomena such as electric potential and electron transfer within the devices is crucial for understanding their operation.

To tackle this challenge, the research group combined a scanning electron microscope with a femtosecond (10^?15 second) laser to measure potential changes in device materials with high temporal resolution. They used this instrument for performing scanning electron microscopy (SEM) of a photoconductive antenna device on a GaAs substrate and obtained SEM images with a resolution of 43 picoseconds. These findings enable the measurement of electrical circuit performance across a bandwidth of 23 GHz, which exceeds the frequencies typically used in 5G communications.

This breakthrough technology offers non-contact, high-speed, three-dimensional measurement of dynamic potential changes at arbitrary points within device structures. It is anticipated to be a vital tool in the development of next-generation electronic devices.

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The corresponding authors and a part of the co-authors were supported by the Innovative Science and Technology Initiative for Security, ATLA, Japan (JPJ004596). This work was partly supported by the grant-in-aid for JSPS KAKENHI (19H00847 and 22H00289).

Original Paper

Title of original paper:

Visualizing the transient response of local potentials on photoconductive antennas using scanning ultrafast electron microscopy

Journal:

ACS photonics

DOI:

10.1021/acsphotonics.3c01532

Correspondence

Professor FUJITA Jun-ichi
Assistant Professor ARASHIDA Yusuke
Institute of Pure and Applied Sciences, University of Tsukuba

Related Link

Institute of Pure and Applied Sciences