A simple Bragg-spacing comparator

172

The absolute lattice parameters of single‐ and polycrystalline materials have been measured to within a few parts per million with a high‐resolution diffractometer. The problems associated with 'zero errors' and sample centring on the goniometer are eliminated and high precision is achieved by virtue of the exceedingly high angular resolution of the instrument. The high‐resolution multiple‐crystal multiple‐reflection diffractometer is used to determine the lattice parameter with a single quick measurement on a range of 'perfect' semiconductor‐substrate materials, layer structures and inhomogeneous samples. The various corrections and alignment procedures associated with this method are discussed.

Section: Introductionmentioning

confidence: 99%

Absolute Lattice-Parameter Measurement

Fewster¹,

Andrew²

1995

172

“…The results obtained in a comparison between the reference, sample 1, and three different samples are shown in Table 1. Sample 2 was grown by Wacker in 1982, samples 3 and 4 were two of the samples used by Ando, Bailey & Hart (1978). Their results are also shown in Table 1.…”

Section: Resultsmentioning

confidence: 99%

“…This shift away from the position of ideal alignment introduces a systematic error in the determination of Ad/d (Larson, 1974). In the triple-beam technique used here, the D beams are tilted out of the T-beam plane by ___ y. Consequently, they have different 6 components for a given non-zero value of q~ and the D-reflection curves occur at different angular positions (Ando, Bailey & Hart, 1978). They coincide only at q~ = 0 and hence provide a reproducible angular reference on the second axis and a straight forward way to adjust the sample tilt.…”

Section: (A) the Effect Of Crystal Tiltmentioning

confidence: 99%

A fast high-accuracy lattice-parameter comparator

Häusermann¹,

Hart²

1990

Self Cite

A method of measuring differences in lattice spacing with an accuracy of 1 part in 108 in a period as short as two minutes is described. The method uses one source of copper radiation and a triple‐axis arrangement. Two of these axes are double‐leaf silicon springs in monolithic crystal assemblies which achieve the high stability required by such measurements. Samples are easily changed and sequences of measurements are performed entirely under computer control. The method is demonstrated by a comparison of the lattice spacings of four samples which reveals differences of up to 60 parts in 108 between silicon crystals of different origins.

“…Other methods using non-superposed beams have been reported (Hart, 1969(Hart, , 1971(Hart, , 1972Ando & Hart, 1975;Hart & Lloyd, 1975;Horn, Kiszenick & Post, 1975;Ando, Bailey & Hart, 1978). Parts-in-107 measurements are reported by Takano & Maki (1973) and Deslattes et al (1974).…”

Section: Introductionmentioning

confidence: 93%

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

Buschert¹,

Meyer²,

Kauffman³

et al. 1983

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.