Ichiro Honjo

Microelectron gun with silicon field emitter

We evaluated the characteristics of single Si field emitters (Si-FEs) from the perspective of their use in electron guns. Since the current fluctuation of Si-FEs strongly depends on the product of vacuum pressure P and emission current I, just as it does for conventional cold field emitters (CFEs), the mechanism of fluctuation was assumed to be similar to that of CFE. Such fluctuations are divided into two regions, the boundary was virtually equal to CFEs, at approximately 3×10−12 Pa A. However, unlike as for CFEs, the emission current of Si-FEs drops abruptly after a certain duration. We found that the integral of PI with the duration time (PIT integral) is almost constant (approximately 1×10−8 Pa A s) in various conditions and therefore assume that it correlates with the emission area of the emitter tip. The current leakage between emitter and gate electrode was found to be caused because of their small size. Responsible for this leakage are hydrocarbon contamination layers that were generated by emitte...

Miniature electron beam column with a silicon micro field emitter

Silicon micro field emitters (Si-MFEs) are expected to be promising as electron sources for their high brightness and ease in making arrayed microcolumns due to small physical size. We have developed a Si-MFE electron gun assembly that produces an electron beam of 1 keV. All components including the Si acceleration electrode are mounted on an integrated circuit (IC) package stem (TO-8) by anodic and eutectic bonding. A high brightness (75 μA/sr) and a long lifetime (>1000 h) have been observed. To overcome the intrinsic emission instability of Si-MFEs, we developed a simple feedback circuit which controls an extraction voltage. The source position shift and the aberration coefficient change caused by stabilization were evaluated analytically and found to be negligible due to the scaling law as applied to micron size. We confirmed that the total emission fluctuation could be stabilized to less than 1% by detecting the absorption current but also found that this detection should be done in the electron beam...

Micro Electron Gun with Silicon Micro Field Emitter

We developed a miniature, high-brightness electron beam system that employs silicon micro field emitters (Si-MFEs) as an electron beam source. Si-MFEs are promising not only for reducing the size of electron guns, but also for increasing their brightness by two or three orders of magnitude compared to that of conventional electron guns. This is possible because they can reduce the electron optical aberrations by about a thousand times. We evaluated the characteristics of single Si-MFE from the perspective of the electron gun. Our micro electron gun was fabricated by ultra high vacuum (UHV) compatible processes and, for the first time, we succeeded in obtaining the SEM images using electrons emitted from Si-MFE.