TEM SAMPLE PREPARATION

摘要

An improved method of preparing ultra-thin TEM samples that combines backside thinning with an additional cleaning step to remove surface defects on the FIB-facing substrate surface. This additional step results in the creation of a cleaned, uniform “hardmask” that controls the ultimate results of the sample thinning, and allows for reliable and robust preparation of samples having thicknesses down to the 10 nm range.

主权项

1. A method of preparing a sample for TEM analysis, the method comprising:
loading a substrate into an ion beam system; separating a sample from the substrate by ion beam milling; extracting the sample from the substrate, said sample having a vertical axis, a top side, and a bottom side; attaching the sample to a sample holder; positioning the sample holder so that the bottom side of the sample is oriented toward the ion beam source and so that the ion beam is parallel to the vertical axis of the sample; thinning the sample by directing the ion beam in a milling pattern that thins at least a portion of the sample to electron transparency; characterized by before thinning the sample, positioning the sample holder so that the ion beam is transverse to the vertical axis of the sample; milling the bottom side of the sample to remove at least of portion of the bottom surface of the sample to produce a uniformly flat surface; and thinning the sample by directing the ion beam in a milling pattern that thins at least a portion of the sample to a thickness of 30 nm or less.