B13-P-06Effective surface treatment of non-conductive materials for orientation analysis by transmission EBSD

Abstract

Electron backscattering diffraction (EBSD) is a very useful technique for crystal orientation analysis by acquiring Kikuchi patterns formed by backscattered electrons [ 1 ]. Non-conductive materials under electron illumination are often suffering from charge-up effects which significantly hamper crystal orientation analysis. Surface coating by a vapour deposition of a conductive solid material is hence very often used to reduce charge-up. However, a special care should be taken to control the deposition thickness because too thick deposition would cause blurred and ambiguous EBSD patterns, whereas too thin deposition could be insufficient to reduce charge-up. A method compensating for charge-up by spraying an ionized gas onto the sample surface [ 2 ] is currently available, though it requires a particular equipment. Transmission EBSD (t-EBSD) is an alternative method to acquire Kikuchi patterns formed by forward-scattered electrons, which transmit through a thin sample like TEM [ 3 ]. In the present study we focus on the two characteristics of t-EBSD: the first one is that t-EBSD can acquire EBSD patterns of the sample even when its surface is contaminated on the side of electron incidence. The second one is that forward-scattered electron has a shorter average traveling path than that of backscattered electrons. Herein, we propose a method for crystal orientation analysis of non-conductive materials, to which t-EBSD is effectively applied with surface coating incorporated. We demonstrate that the surface coating on non-conductive samples exerts not only little influence on the clarity of t-EBSD patterns but also helps better identification of crystal orientation by reducing charge-up.