Patent ID: 7449682

Claim:
A method for use in characterizing a sample, wherein the method comprises: collecting depth profile data at each of a plurality of depths of the sample, each depth corresponding to a sample surface, wherein one or more of the plurality of depths of the sample are provided by removing material from the sample during material removal intervals resulting in sample surfaces at the one or more depths of the sample, and further wherein collecting depth profile data at each of the plurality of depths of the sample comprises: irradiating the sample with x-rays resulting in the escape of photoelectrons therefrom; detecting photoelectrons escaping from the sample, wherein detecting the photoelectrons comprises providing an analyzer comprising an input lens receptive of photoelectrons, the input lens having a central axis extending therethrough, and positioning the input lens such that the central axis of the input lens is at an analyzer angle relative to the sample surface in a range of about 45 degrees to about 90 degrees; and generating a signal representative of the detected photoelectrons; using the depth profile data collected for a first and second depth to characterize the sample at the first depth, wherein the second depth is at a position deeper in the sample than the first depth, and wherein characterizing the sample at the first depth comprises removing the depth profile data collected for the second depth from the depth profile data collected for the first depth; and using the depth profile data collected for the first and second depth to calibrate the depth profile of a second sample, wherein the depth profile of the second sample is collected non-invasively.