A scanning tunneling microscope dedicated to in situ experiments under the irradiation of highly brilliant hard-X-rays of synchrotron radiation has been developed. In situ scanning tunneling microscopy (STM) observation was enabled by developing an accurate alignment system in ultrahigh vacuum. Despite the noisy conditions of the synchrotron radiation facility and the radiation load around the probe tip, STM images were successfully obtained at atomic resolution. Tip-current spectra were obtained for Ge nano-islands on a clean Si(111) surface by changing the incident photon energy across the Ge absorption edge. A current modification was detected at the absorption edge with a spatial resolution of the order of 10 nm.
The correlation between threshold voltage (VT) and channel boron concentration in silicon-based 65 nm node negative-type metal-oxide-semiconductor field-effect transistors was studied by atom probe tomography (APT). VT values were determined for one million transistors in a single chip, and transistors having a ±4σ deviation from the median VT were analyzed using APT. VT and the channel boron concentration were positively correlated. This is consistent with the relationship between the average boron concentration of wafers implanted with different channel doses and the median VT of the million transistors. APT is suitable for the study of dopant-distribution-based device failure mechanisms.
In situ scanning tunneling microscopy (STM) with highly brilliant hard X-ray irradiation was enabled at SPring-8. To obtain a good signal-to-noise ratio for elemental analysis, an X-ray beam with a limited size of '10 mm was aligned to a specially designed STM stage in ultrahigh vacuum. Despite various types of noises and a large radiation load around the STM probe, STM images were successfully observed with atomic resolution. The use of a new system for elemental analysis was also attempted, which was based on the modulation of tunneling signals rather than emitted electrons. Among tunneling signals, tunneling current was found to be better than tip height as a signal to be recorded, because the former reduces markedly the error of measurement. On a Ge nanoisland on a clean Si(111) surface, the modulation of tunneling current was achieved by changing the incident photon energy across the Ge absorption edge.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.