Atomic Resolution Electronic Structure in Device Development

Abstract Recently, we have seen that the STEM can produce 0.12-0.26nm atomic resolution image detail in Annular Dark Field (ADF) mode even at modest acceleration voltages and in partnership with EELS for bonding studies. In the semi-conductor field, we are in a good position to take advantage of this imaging capability, because several atomic plane spacings range from 0.14 - 0.26 nm in the [100], [011] and [111] projections of Si and Ge. Figure 1. shows a result for the Si [111] projection obtained in the IBM VG Microscopes HB501UX, modified to produce a 0.19nm probe at 120KeV. The image has been filtered to remove spatial distances shorter than 0.15 nm, yielding the inset power spectrum. Each bright spot in the image corresponds to a single atomic column, separated from its neighbors by 0.19 nm. At 20Mx, the atom columns show enough contrast on the screen to allow astigmatism correction. These are similar to those discussed previously.