High spatial resolution imaging of helium isotope by TOF-SNMS

Laser ionization mass nanoscope is a time-of-flight sputtered neutral mass spectrometer associated with laser post-ionization by tunneling effect. A spherical and chromatic aberration corrector is installed in the primary ion column. The lateral spatial resolving power of He imaging of solid surface has been evaluated by scanning image using a probe diameter of 90 nm from crater edge slope of a He ion-implanted Si substrate. Helium distribution from the scanning image is quantitatively equivalent with depth profiling analysis from surface of the same substrate, indicating that spatial resolving power of 20 nm for depth resolution has been achieved on the He scanning image through use of oblique incident effect of the primary beam.