Hard x-ray microscope with submicrometer spatial resolution

Abstract

A high-resolution hard x-ray microscope is described. This system is capable of detecting line features as small as 0.6 µm in width, and resolving line pairs 1.2-µm wide and 1.2-µm apart. Three types of two-dimensional image detectors are discussed and compared for use with hard x rays in high resolution. Principles of x-ray image magnification are discussed based on x-ray optics and diffraction physics. Examples of applications are shown in microradiography with fiber reinforced composite materials (SiC in Ti3Al Nb) and in diffraction imaging (topography) with device patterns on a silicon single crystal. High-resolution tomography has now become a reality.

High resolution diffraction imaging of crystals grown in microgravity and closely related terrestrial crystals

“…We have applied a CCD area detector to image the GaAs test crystal in transmission (41). Figure 83 contains two forward (0-beam) transmission diffraction images of the high-quality GaAs crystal, using 220 diffraction planes and 13.5 keV radiation.…”

“…To demonstrate such a need for crystal growth and fabrication science and engineering we show some results of imaging such device structures in a In(GaAs)P laser diode [41][42], in which many layers are produced by OMVPE (organometallic vapor phase epitaxy) and subsequent doping of different atoms, and are required to be highly lattice coherent (almost nonexistent mismatch in lattices) among themselves and with their substrates. It is extremely difficult to obtain images of the layer6 with good contrast in such a material using microradiography.…”

“…Aided by micro-manipulation of angles and positions of the sample and a zooming capability, the x-ray microscope can view the diffraction image of particular layers or layer sections [41][42]. Mm thick layers located 20 " 50 Am below the surface (within the substrate crystal).…”

“…Figure 85 shows a microradiograph of a rather special specimen crystal consisting of a 0.38 mm-thick Si single crystal wafer upon which has been deposited patterns of lines and contact pads of Pd with a thickness of 0.15 dam. The image was obtained at a magnification of 79 with 12.25 keV x-rays (41)(42] (43). At this magnification one CCD pixel represents 0.25 µm.…”

“…Without moving the microscope from the position set for microradiography, the O-beam image can be viewed on the ;monitor screen merely by rotating the sample. Figure 86 shows a microradiographic image of this sample to be compared with Figure 87 which is the 0-beam image taken in transmission for the 220 diffraction with the microscope set for the same magnification, 22 X at 8.3 keV [41](42) (43). In dynamical diffraction, a s';:rain field acts as a scattering center and produces a black and white image (6].…”