NU 2017-016

Inventors

Vinayak P. Dravid*

Benjamin Myers

Karl A. Hujsak

Short Description

An electron microscopy and image processing system for the aquisition and reconstruction of crystalline image data.

Background

Crystal phase and orientation are crucial microstructural properties that influence the mechanical, electrical, and optical properties of structures and devices. Determining crystal phase and orientation across a large sample area with high throughput and spatial resolution generates valuable insight into a materials structure and properties for optimizing device (e.g. semiconductor) performance. Current technologies that are used to perform crystal image mapping (e.g., electron backscatter diffraction (EBSD) and selected area channeling patterns (SACP)) require specialized instrumentation beyond the standard electron microscope or ion microscope, which is expensive and operationally labor-intensive.

Abstract

Northwestern researchers have developed a stage-rocked system which physically tilts/rotates a sample with image acquisition software.  This system automatically aligns captured images to generate crystal phase and orientation mapping across large areas. The new technique constructs electron channeling patterns for use in crystal orientation mapping by capturing fully rastered backscattered electron images. Dubbed “Orientation Mapping by Electron Channeling (OMEC),” it offers advantages over current technologies in terms of strain mapping, quality control in bulk or thin film materials and local defect analysis. Moreover, this system is ultra-low cost and offers higher contrast and angular resolution. Furthermore, because of the nature of the data acquisition, machine learning techniques can be applied for predictive sampling and inpainting from sparse data sets which can dramatically reduce acquisition time. The image acquisition software is easily incorporated into existing software platforms while the only requirement of the microscope is a computer-controlled, motorized stage and an attached computer for image processing.

Applications

• Analysis of crystalline microstructural properties

Advantages

• Low cost
• Simple integration into existing systems
• Improved strain mapping, quality control and defect analysis
• High contrast and angular resolution
• High throughput

Publications

Hujsak KA, Myers BD, Grovogui J and Dravid VP (2018) Stage-Rocked Electron Channeling for Crystalline Orientation Mapping.  Nature Scientific Reports. 8: 5175.

IP Status

A provisional patent application has been filed.