Effects of tetragonal distortion in thin expitaxic films on electron channeling patterns in scanning electron microscopy

Abstract

The elastic strain state in a 25 nm (In,Ga)As epitaxic film deposited on a (001) GaAs substrate includes a Poisson expansion perpendicular to the interface. This creates a tetragonally distorted lattice in the film which shifts high-order Laue-zone (HOLZ) lines in electron channeling patterns (ECP) from the film compared to ECP's from pure GaAs. The line shifts are predictable, thereby allowing measurement of elastic strains parallel and perpendicular to the film/ substrate interface independently. The technique appears to have an accuracy close to 0.2%.

Measuring the Strain Sensitivity in Si (001) Electron Channeling Patterns Using Higher-order Laue Zone Line Shifts

“…To corroborate this result, the entire procedure has been replicated for a series of dynamically simulated SACPs over the same voltage range, which is in good agreement with the experimental SACPs. This sensitivity measurement improves upon previous attempts for ECP HOLZ line analysis [3].…”

Electron diffraction based techniques in scanning electron microscopy of bulk materials

“…The best accuracy that has been quoted is 3 parts in 10 4 obtained by Walker and Booker (1982) for lattice parameter measurements in Si and GaP using lines such as {10,10,0} which are not routinely visible in ECP. Other workers have obtained strain sensitivities of 2 parts in 10 3 (Kozubowski, Keller and Gerberich 1991) but even here the {660} lines used would be readily removed by any plastic deformation in the crystal.…”