Presentation Information
[9p-N301-1][Invited Talk] Nano-scale electric field and charge imaging using scanning transmission electron microscopy
〇Satoko Toyama1, Takehito Seki1, Naoya Shibata1,2 (1.Univ. of Tokyo, 2.JFCC)
Keywords:
scanning transmission electron microscopy,GaN
As semiconductor devices are miniaturized, their performance is increasingly dictated by nano-scale electric and charge field distributions, making their direct measurement crucial. We utilize Differential Phase Contrast Scanning Transmission Electron Microscopy (DPC STEM), a technique to visualize these internal electromagnetic fields by detecting the deflection of a scanning electron beam caused by Coulomb or Lorentz forces. A major challenge has been the quantitative analysis at crystalline interfaces due to diffraction artifacts. We have recently developed a method to suppress these artifacts, enabling quantitative observation of interfacial fields. This breakthrough has allowed for the direct visualization of the two-dimensional electron gas (2DEG) at a GaN-based heterointerface. Our work also includes the clarification of the correlation between charge and segregation at oxide grain boundaries and the visualization of charge at ferroelectric domain walls. Our technique is a powerful tool for elucidating the local charge states at interfaces and defects to understand the origin of material properties.