- SEMI MF1630 - Test Method for Low Temperature FT-IR Analysis of Single Crystal Silicon for III-V Impurities
This Standard was technically approved by the Silicon Wafer Global Technical Committee. This edition was approved for publication by the global Audits and Reviews Subcommittee on February 1, 2018. Available at www.semiviews.org and www.semi.org in July 2018; originally published by ASTM International as ASTM F1630; previously published September 2012.
Electronic grade polysilicon producers and users rely on low temperature Fourier transform infrared (LTFT-IR) spectroscopy to evaluate polysilicon for quality assurance and research purposes.
LTFT-IR spectroscopy identifies and quantitates boron, phosphorus, aluminum, arsenic, indium, antimony, and gallium.
LTFT-IR spectroscopy can be applied to FZ, CZ, or other single crystal silicon (either doped or undoped) up to the concentration limits given in § 2.2.
The measurement of carbon in silicon at low temperature can be accomplished concurrently in accordance with SEMI MF1391. The carbon can be measured at lower concentrations at <15 K than is possible at room temperature because the two-phonon band transmission is increased by a factor of two allowing greater throughput to the detector that results in an increased signal to noise ratio. Also, the carbon adsorption band narrows from a full width half maximum (FWHM) of 5 to 6 cm-1 to a FWHM of 2.5 to 3.0 cm-1 at these low temperatures.
This Test Method covers the determination of electrically active boron, phosphorus, arsenic, aluminum, antimony, and gallium concentration in single crystal silicon.
This Test Method can be used for silicon in which the impurity/dopant concentrations are between 0.01 and 5 ppba for each of the electrically active elements.
The concentration for each impurity/dopant can be obtained by application of Beer’s Law. Calibration factors are given for each element.
Referenced SEMI Standards
SEMI M59 — Terminology for the Silicon Technology
SEMI MF723 — Practice for Conversion Between Resistivity and Dopant Density for Boron-Doped, Phosphorus-Doped, and Arsenic-Doped Silicon
SEMI MF1391 — Test Method for Substitutional Atomic Carbon Content of Silicon by Infrared Absorption
SEMI MF1723 — Practice for Evaluation of Polycrystalline Silicon Rods by Float-Zone Crystal Growth and Spectroscopy