Photoelastic and X‐ray topographic studies of residual stress and lattice deformation in GaAs single crystals

Abstract

The GaAs crystals, grown with three different methods were siinultaneously studied by means of photoelastic and X-ray topographic methods. The methods provide complementary information about lattice deformation. The correspondence between interplanar distance changes and photoelastically measured stress values and the connection between cellular structure and high stress values were also found.Die GaAs Einkristalle, hergestellt mit drei vorschiedenen Methoden, werden mit den photoelastischen und r6ntgentopographischcn Methoden gleichzeitig studiert. Beide Methoden ergaben komplementiire Informationen uber die Deformation vom KristallCitter. Wir fanden auch die Abhangigkeit zwischen gemessenem StreB-Niveau und der Zellular-S truktur .

Automated birefringence dispersion measurements

“…In figure 8, one can see a plane polariscope picture of an undoped GaAs wafer originating from a crystal obtained approximately 20 years ago. Mosaic structure like that evidenced on this photo, as well as also detected in this sample by x-ray methods reported elsewhere [17], is still not obtained in currently manufactured crystals. However, this could be a good sample for testing a new method, like the one presented here.…”

Synchrotron X‐ray investigation of La0.3Sr0.7Al0.65Ta0.35O3 crystals

“…The effects of lattice deformation connected with high concentration of dislocation revealed by means of double-crystal topography were in particular shown in [9,10]. Similar effects should appear at density of dislocations corresponding to that of observed etch pits on the level exceeding 10 4 cm -2 .…”

X-Ray Topographic Investigation of Cellular Structure and its Relation to another Defects in Various Types of GaAs Single-Crystals

“…An extreme case was found in a bad quality crystal where the blocks grouping the cellular stucture have the misorientation of single degrees. Our former investigation with double-crystal and plane polariscope method [10] pointed that the residual stress distribution is of dominant radial character and is more regular than the deformation pattern.…”