In electron holography, electrostatic potential is measured by measuring the phase difference between Ndoped and P-doped regions of the semiconductor devices . The electric potential is proportional to the phase shift, which is related to the dopant concentration and MIP. Electron beam passing through the sample interferes with the reference beam and form interference fringe over the image of the sample. Fourier transform on the holographic image is used to obtain an image in a reciprocal space where one of the two sidebands is selected, and the main beam is masked off. Inverse Fourier transfer on one of the selected sidebands is performed to obtain phase map as well as amplitude map. The amplitude image is like regular TEM image, while phase image can only be measured through interference imaging method. This allows us to measure the lattice strain along in-plane (XX) and out-of-plane direction (YY). In a fully strained lattice, we expect to see difference in lattice constants along YY direction only.