A double-source double-crystal X-ray spectrometer for high-sensitivity lattice-parameter difference measurements

Abstract

A method of measuring the difference between the lattice parameter of a region of an unknown sample and that of a region of a standard reference crystal to a sensitivity of 1 part in 109 is presented. Problems inherent in multiple‐beam arrangements due to sample strains and non‐uniformity have been overcome by the use of a new double‐source arrangement in which the two X‐ray beams sample the same spot on a crystal under study. Ways of identifying and preventing errors from significant mechanical and thermal effects arising in the sensitivity region explored are indicated.

A fast high-accuracy lattice-parameter comparator

“…For example, Bushert, Pace, Inzaghi & Merlini (1980) reached an accuracy of 3 parts in 108 in comparative measurements on silicon using a double-beam triple-crystal spectrometer. More recently, Buschert, Meyer, Stuckey Kauffman & Gotwals (1983) measured differences in lattice parameters with an accuracy of 1 part in 109 and demonstrated that the accuracy of measuring techniques had overtaken the reproducibility of the lattice parameter of silicon across a few millimetres of the best hyperpure dislocation-free crystal. More recently, Buschert, Meyer, Stuckey Kauffman & Gotwals (1983) measured differences in lattice parameters with an accuracy of 1 part in 109 and demonstrated that the accuracy of measuring techniques had overtaken the reproducibility of the lattice parameter of silicon across a few millimetres of the best hyperpure dislocation-free crystal.…”

“…The most accurate measurement reported by Hart (1981) required three X-ray sources and three detectors. In order to reach the accuracy of one part in 10 9, Buschert et al (1983) used two crystals, three sources, three detectors and an elaborate thermally controlled and insulated experimental set up. In order to reach the accuracy of one part in 10 9, Buschert et al (1983) used two crystals, three sources, three detectors and an elaborate thermally controlled and insulated experimental set up.…”

“…All these techniques were reviewed by Hart (1981). More recently, Buschert, Meyer, Stuckey Kauffman & Gotwals (1983) measured differences in lattice parameters with an accuracy of 1 part in 109 and demonstrated that the accuracy of measuring techniques had overtaken the reproducibility of the lattice parameter of silicon across a few millimetres of the best hyperpure dislocation-free crystal. 0021-8898/90/010063-07503.00…”

“…Buschert et al (1980) used one source, three crystals and four detectors to reach an accuracy of a few parts in 108. In order to reach the accuracy of one part in 10 9, Buschert et al (1983) used two crystals, three sources, three detectors and an elaborate thermally controlled and insulated experimental set up. Furthermore, almost all these techniques require custom-built equipment, setting up by experts and many hours to establish stable conditions and to make measurements.…”

Misfit stress in p/p+ epitaxial silicon wafers: effect and elimination

“…To investigate the characteristics of the lattice compensation effect by the cGdoping of B and Ge, precision lattice parameter measurements were carried out on grown p+ silicon with a range of C G~/ C B , using a double-crystal-double-beam X-ray diffraction method (8). In this method, the difference in lattice spacings of a high-index lattice plane of the sample and the standard is measured with a sensitivity of 1 part in IOg.…”