Scanning tunneling microscope(STM) for an advanced device processes

A scanning tunneling microscope (STM) was developed to evaluate advanced device process which needs atomic or nm order control. The STM has an atomic resolution topographic imaging mode, a fast probe scanning and imaging mode, and a material characterization imaging mode. The features of the instrument are : (1) A conversion technology of tunneling current fluctuation to gap fluctuation for a high resolution STM image, (2) a correction technology of probe control error in fast scanning for an in-situ observation and (3) an AD-DA conversion technology to hold the probe position fixed for a Current Imaging Tunneling Spectroscopy (CITS). Various STM images support that the STM provides a high resolution (around 2 Å in X and Y, and less than 0.1 Å in Z), a fast imaging of 2 s/flame (150 Å × 150 Å) and simultaneous measurement of both STM image and current image. (7×7) reconstruction Si (111) surface VTR images, (√3 × √3) Au construction on Si (111), pn junction structure and the boundary, and groove shape and recorded pit structure in optical disc device are presented and discussed here. The STM is found to be feasible to evaluate an Molecular Beam Epitaxy (MBE) process, a fine pn junction and an ultra high packed structure.