Oxford Instruments Nanotechnology Tools Limited

Oxford Instruments Analytical Limited

Link Analytical Limited

Oxford Instruments Nonotechnology Tools Unlimited

Peter John Statham

Angus Bewick

Charles Penman

Marcus Jacka

Ian Richard Barkshire

Christian Lang

James Corrin

Cheryl Hartfield

Philippe Pinard

Simon Burgess

James Holland

Anthony Hyde

A method and system for analyzing a specimen in a microscope are disclosed. The method comprises: acquiring a series of compound image frames using a first detector and a second detector, different from the first detector, wherein acquiring a compound image frame comprises: causing a charged particle beam to impinge upon a plurality of locations within a region of a specimen, the region corresponding to a configured field of view of the microscope, the microscope being configured with a set of microscope conditions, monitoring, in accordance with the configured microscope conditions, a first set of resulting particles generated within the specimen at the plurality of locations using the first detector so as to obtain a first image frame, monitoring, in accordance with the configured microscope conditions, a second set of resulting particles generated within the specimen at the plurality of locations using the second detector, so as to obtain a second image frame, wherein each image frame comprises a plurality of pixels corresponding to, and derived from the monitored particles generated at, the plurality of locations within the region, for each pixel of the second image frame, if the configured microscope conditions are the same as those for a stored second image frame of an immediately preceding acquired compound frame in the series, and if the respective pixel corresponds to a location within the region to which a stored pixel comprised by said stored second image frame corresponds, combining said stored pixel with the pixel so as to increase the signal-to-noise ratio for the pixel, and combining the first image frame and second image frame so as to produce the compound image frame, such that the compound image frame provides data derived from, for each of the plurality of pixels, the particles generated at the corresponding location within the region and monitored by each of the first detector and second detector; and displaying the series of compound image frames in real-time on a visual display.

Navigation for electron microscopy

A method and system for processing a diffraction pattern image obtained in an electron microscope are disclosed. The method comprises, according to a first set of microscope conditions, causing an electron beam to impinge upon a calibration specimen so as to cause resulting electrons to be emitted therefrom and monitoring the resulting electrons using a detector device so as to obtain a calibration image comprising a plurality of pixels having values, the first set of microscope conditions being configured such that the calibration image includes substantially no electron diffraction pattern; obtaining, from the calibration image, a gain variation image comprising a plurality of pixels, each having a value representing relative detector device gain for a corresponding pixel of the calibration image; according to a second set of microscope conditions, causing an electron beam to impinge upon a target specimen so as to cause resulting electrons to be emitted therefrom and monitoring the resulting electrons using the detector device so as to obtain a target image comprising a plurality of pixels having values, the second set of microscope conditions being configured such that the target image includes an electron diffraction pattern; and for each pixel of the target image, removing from the pixel value, in accordance with the value of the corresponding pixel of the gain variation image, the contribution to the pixel value of the relative detector device gain, so as to obtain a gain variation-corrected image.

System for electron diffraction analysis

A computer-implemented method of image processing for materials analysis is provided. At least three image datasets are obtained, these representing intensity values of image pixels and being in common spatial registration. The image datasets are processed so as to assign a comparison measure to each pair of image datasets, the comparison measure for a given pair of image datasets being representative of the difference between the spatial intensity information within the pair. A number of image datasets are then selected using the comparison measures. A color difference measure is defined which represents the difference between pairs of colors of a color set. Colors are assigned to the selected image datasets such that pairs of the selected image datasets which have substantially different spatial intensity information are assigned respective colors which have a substantially different color difference measure. A number of the selected image datasets are then combined together to form an output color image dataset for the formation of a color image. The combination is such that each pixel of the color image takes on a color according to the relative intensities and colors of the selected image datasets so that if the pixel intensity of one dataset is substantially greater than the sum of the pixel intensities for all the other selected datasets, then the output color in the respective part of the image will substantially match the color assigned to that image dataset.

Material identification using multiple images

An x-ray analysis apparatus comprises an electron beam assembly for generating a focused electron beam within a first gas pressure environment. A sample assembly is used for retaining a sample within a second gas pressure environment such that the sample receives the electron beam from the electron beam assembly and such that the gas pressure in the second gas pressure environment is greater than the gas pressure within the first gas pressure environment. An x-ray detector is positioned so as to have at least one x-ray sensor element within the first gas pressure environment. The sensor element is mounted to a part of the electron beam assembly which is proximal to the sample assembly and further arranged in use to receive x-rays generated by the interaction between the electron beam and the sample.

X-ray analysis in air

A method is provided of measuring the mass thickness of a target sample for use in electron microscopy. Reference data are obtained which is representative of the X-rays () generated within a reference sample () when a particle beam () is caused to impinge upon a region () of the reference sample (). The region () is of a predetermined thickness of less than 300 nm and has a predetermined composition. The particle beam () is caused to impinge upon a region () of the target sample (). The resulting X-rays () generated within the target sample () are monitored () so as to produce monitored data. Output data are then calculated based upon the monitored data and the reference data, the output data including the mass thickness of the region () of the target sample ().

Method for measuring the mass thickness of a target sample for electron microscopy

A method is provided for processing a spectrum, obtained using a particle detection system, so as to reduce spectrum artifacts arising from unresolved particle events in the detection system. An input spectrum is obtained which contains artifacts due to 'pile up' in the detector. A first effect upon the input spectrum of pairs of unresolved particle events is evaluated and a first corrected input spectrum is generated which comprises the input spectrum with the first effect removed. The effect of a pairs of unresolved particle events is then evaluated for this first corrected input spectrum so as to generate a second corrected input spectrum which comprises the input spectrum with the second effect removed. An output spectrum is then generated based upon a combination of the first and second corrected input spectra. The use of the method in improving sum spectra is also discussed.

Method of processing a particle spectrum

A method is provided of reducing the thickness of a region of a target sample. Reference data is obtained that is representative of x-rays generated by a particle beam being directed upon part of a reference sample under a first set of beam conditions. Under a second set of beam conditions the particle beam is directed upon the region of the target sample. The resultant x-rays are monitored as monitored data. Output data are then calculated based upon the reference and the monitored data. Material is then removed from the region, so as to reduce its thickness, in accordance with the output data.

Method of reducing the thickness of a target sample

An apparatus for detecting one or each of Kikuchi and Kossel diffraction patterns is provided. The apparatus comprises an electron column adapted in use to provide an electron beam () directed to wards a sample (), the electron beam () having an energy in the range 2 keV to 50 keV, and a particle detector () for receiving and counting particles () from the sample () due to interaction of the electron beam () with the sample (), the detector comprising an array of pixels () and having a count rate capability of at least 1000 particles per second for each pixel. The particle detector () is further adapted to provide electronic energy filtering of the received particles in order to count the received particles which are representative of the said diffraction pattern.

Apparatus and method for performing microdiffraction analysis

A charged particle analyzer () comprises a first non-imaging electrostatic lens () for receiving charged particles having divergent, trajectories and for converting the said trajectories into substantially parallel trajectories. At least one planar filter () is provided for receiving the charged particles having the substantially parallel trajectories and for filtering the charged particles in accordance with their respective energies. A second non-imaging electrostatic lens () receives the energy filtered charged particles and selectively modifies their trajectories as a function of their energies. A charged particle detector () then receives the charged particles in accordance with their selectively modified trajectories.

Charged particle analyser and method using electrostatic filter grids to filter charged particles

A method of determining the feasibility of a proposed structure analysis process is disclosed. The process involved the electron beam excitation of x-rays from a multi-layered structure. The method comprises generating predicted x-ray data represents the x-ray excitation response of the multi-layered structure according to one or more sets of process conditions. The x-ray data are generated using structure data defining the structure and composition of the layers. The effects upon the x-ray data of changes to the structure data are then analyzed in accordance with one or more predetermined feasibility criteria, so as to determine the feasibility of performing the proposed structure analysis process upon the multi-layered structure.

Method of determining the feasibility of a proposed structure analysis process

A method and apparatus for quantitative analysis of a material in which an electron beam is caused to impinge upon the material are described. The method comprises detecting low loss electrons (LLEs) received from a first region of the material due to interaction with the electron beam and generating corresponding LLE data. The method further comprises detecting x-rays received from a second region of the material due to interaction with the electron beam and generating corresponding x-ray data, wherein the first and second regions overlap, and analysing the LLE data together with the x-ray data so as to generate compositional data representative of the composition of the first region.

Method for quantitative analysis of a material

A method is provided of calculating the structure of an inhomogeneous sample in which an electron beam is used to cause excitation of x-rays from the sample under known conditions of beam energy and geometry with respect to the sample. Notably the beam current is unknown. Measured x-ray intensity data for the sample corresponding to one or more sets of beam conditions and beam currents are firstly obtained, together with comparative x-ray intensity data for samples having known structures. A beam current factor for each beam condition is estimated and effective x-ray intensity data for each of the sets of conditions are then calculated using the measured and comparative x-ray intensity data and the beam current factor. The structure of the sample is then calculated for each of the sets of conditions using the effective x-ray intensity data. Predicting x-ray intensity data are produced corresponding to the calculated structure and compared with the effective x-ray intensity data. These steps are repeated using revised beam current factors until the predicted and effective x-ray intensity data achieve a predetermined similarity condition.

Method of calculating the structure of an inhomogeneous sample

A method of identifying a material using an x-ray emission characteristic is provided. X-ray data representing a monitored x-ray emission characteristic is obtained from a specimen in response to an incident energy beam. A dataset is also obtained, this comprising composition data of a plurality of materials. The material of the specimen is contained within the dataset. Predicted x-ray data are calculated for each of the materials in the dataset using the composition data. The obtained and the predicted x-ray data are compared and the likely identity of the material of the specimen is determined, based upon the comparison.

Method and apparatus for material identification

A method of analyzing a dataset of spectra is provided in which each spectrum has a count value for each of a number of parameter values within a parameter range. The method is for identifying one or more parameter values that exhibit a significant variation within the dataset. A dataset of spectra is obtained and a statistical analysis is applied to the count values for each of the parameter values. The result of the analysis for each parameter value is a function of the variation in the count values. A spectrum that is representative of at least part of the dataset of spectra is then displayed together with the results of the statistical analysis. A corresponding computer program and system for performing the method are also disclosed.

Growing community of inventors

High Wycombe, United Kingdom

Peter John Statham