A Working Method for Adapting the (SEM) Scanning Electron Microscope to Produce (STEM) Scanning Transmission Electron Microscope Images

Author(s):  
Edward Coyne

Abstract This paper describes the problems encountered and solutions found to the practical objective of developing an imaging technique that would produce a more detailed analysis of IC material structures then a scanning electron microscope. To find a solution to this objective the theoretical idea of converting a standard SEM to produce a STEM image was developed. This solution would enable high magnification, material contrasting, detailed cross sectional analysis of integrated circuits with an ordinary SEM. This would provide a practical and cost effective alternative to Transmission Electron Microscopy (TEM), where the higher TEM accelerating voltages would ultimately yield a more detailed cross sectional image. An additional advantage, developed subsequent to STEM imaging was the use of EDX analysis to perform high-resolution element identification of IC cross sections. High-resolution element identification when used in conjunction with high-resolution STEM images provides an analysis technique that exceeds the capabilities of conventional SEM imaging.

Author(s):  
Oliver C. Wells ◽  
P.C. Cheng

In this discussion the words “high resolution imaging” of a solid sample in the scanning electron microscope (SEM) mean that details can be resolved that are considerably smaller than the penetration depth of the incident electron beam (EB) into the specimen. “Atomic resolution” in either the transmission electron microscope (TEM) or scanning transmission electron microscope (STEM) means that columns of atoms are resolved.Image contrasts in the backscattered electron (BSE) image are strongly affected by the specimen tilt and by the position and energy sensitivity of the BSE detector. The expression “BSE image” generally implies that the specimen is normal to the beam and the detector is above it. This shows compositional variations in the specimen with a spatial resolution limited by the spreading of the EB during the initial stages of penetration. This is similar in basic principle to the Z-Contrast method in the STEM that shows atomic resolution from a thinned single crystal mounted in the magnetic field of the focusing lens.


Author(s):  
M. Kersker ◽  
C. Nielsen ◽  
H. Otsuji ◽  
T. Miyokawa ◽  
S. Nakagawa

Historically, ultra high spatial resolution electron microscopy has belonged to the transmission electron microscope. Today, however, ultra high resolution scanning electron microscopes are beginning to challenge the transmission microscope for the highest resolution.To accomplish high resolution surface imaging, not only is high resolution required. It is also necessary that the integrity of the specimen be preserved, i.e., that morphological changes to the specimen during observation are prevented. The two major artifacts introduced during observation are contamination and beam damage, both created by the small, high current-density probes necessary for high signal generation in the scanning instrument. The JSM-890 Ultra High Resolution Scanning Microscope provides the highest resolution probe attainable in a dedicated scanning electron microscope and its design also accounts for the problematical artifacts described above.Extensive experience with scanning transmission electron microscopes lead to the design considerations of the ultra high resolution JSM- 890.


2001 ◽  
Vol 7 (S2) ◽  
pp. 822-823
Author(s):  
Stephen K. Chapman

I was trained as a transmission electron microscope engineer in the mid 1960s. I took resolution tests at least once each year and calibrated all of the microscopes that I attended, it was considered a standard procedure for those maintaining an instrument. Moving into the scanning electron microscope field in the mid 1970s it was natural to carry this practice over to that instrument, but in those days this was considered to be extreme. Now, as a consultant in electron microscopy, I routinely carry out SEM resolution, magnification calibration and contamination rate tests on the instruments that I use. I train operators in the role of preventative maintenance and encourage them to know as much as possible about their instruments as this increases their ability to fault find and maintain their own instruments.Resolution - in many laboratories most tungsten hairpin instruments are set up for extended filament life rater than for high resolution.


2019 ◽  
Vol 26 (08) ◽  
pp. 1950047
Author(s):  
JIANING LI ◽  
MOLIN SU ◽  
LIWEI ZHANG

The composites were obtained by the argon-arc cladding (AAC) of the Deloro22-Si3N4-Fe pre-placed powders on a TA1 titanium alloy substrate, which improved the wear resistance of the substrate. Such composites were investigated by means of the scanning electron microscope (SEM), the microscope and the high resolution transmission electron microscope (HRTEM). The results indicated that the amorphous phases were produced in such AAC composites, increasing the wear resistance. With addition of Y2O3, lots of the micro/nanoscale particles were formed, which further improved the wear resistance of such AAC composites.


2008 ◽  
Vol 600-603 ◽  
pp. 55-58
Author(s):  
Mamoru Imade ◽  
Takashi Ogura ◽  
Masahiro Uemura ◽  
Fumio Kawamura ◽  
Masashi Yoshimura ◽  
...  

We have achieved the first successful growth of 2H-SiC single crystals using the C-Li-Si melt system. Li-Si melt, whose melting point is lower than 1000 oC, was chosen because the 2H-SiC polytype is more stable at lower temperatures than other polytypes such as 3C-, 4H-, and 6H-SiC. Many hexagonal-shaped crystals of approximately 100 m in diameter were observed via a scanning electron microscope (SEM). A high resolution transmission electron microscope (HR-TEM) lattice image of the grown crystals showed a periodical structure with A-B stacking along the <0001> direction. These results indicated that the Li-based flux was useful for growing bulk 2H-SiC single crystals.


Author(s):  
K. Shibatomi ◽  
T. Yamanoto ◽  
H. Koike

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.


Author(s):  
S. Takashima ◽  
H. Hashimoto ◽  
S. Kimoto

The resolution of a conventional transmission electron microscope (TEM) deteriorates as the specimen thickness increases, because chromatic aberration of the objective lens is caused by the energy loss of electrons). In the case of a scanning electron microscope (SEM), chromatic aberration does not exist as the restrictive factor for the resolution of the transmitted electron image, for the SEM has no imageforming lens. It is not sure, however, that the equal resolution to the probe diameter can be obtained in the case of a thick specimen. To study the relation between the specimen thickness and the resolution of the trans-mitted electron image obtained by the SEM, the following experiment was carried out.


Author(s):  
S. Saito ◽  
H. Todokoro ◽  
S. Nomura ◽  
T. Komoda

Field emission scanning electron microscope (FESEM) features extremely high resolution images, and offers many valuable information. But, for a specimen which gives low contrast images, lateral stripes appear in images. These stripes are resulted from signal fluctuations caused by probe current noises. In order to obtain good images without stripes, the fluctuations should be less than 1%, especially for low contrast images. For this purpose, the authors realized a noise compensator, and applied this to the FESEM.Fig. 1 shows an outline of FESEM equipped with a noise compensator. Two apertures are provided gust under the field emission gun.


Author(s):  
John R. Devaney

Occasionally in history, an event may occur which has a profound influence on a technology. Such an event occurred when the scanning electron microscope became commercially available to industry in the mid 60's. Semiconductors were being increasingly used in high-reliability space and military applications both because of their small volume but, also, because of their inherent reliability. However, they did fail, both early in life and sometimes in middle or old age. Why they failed and how to prevent failure or prolong “useful life” was a worry which resulted in a blossoming of sophisticated failure analysis laboratories across the country. By 1966, the ability to build small structure integrated circuits was forging well ahead of techniques available to dissect and analyze these same failures. The arrival of the scanning electron microscope gave these analysts a new insight into failure mechanisms.


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