This reference Test Method  covers the determination of substitutional carbon concentration in single crystal silicon. Because carbon may also reside in interstitial lattice positions when in concentrations near the solid solubility limit, the results of this Test Method may not be a measure of the total carbon concentration at such concentrations.
 

The useful range of carbon concentration measurable by this Test Method is from the maximum amount of substitutional carbon soluble in silicon down to about 0.1 parts per million atomic (ppma), that is, 5 × 1015 cm3 for measurements at room temperature, and down to about 0.01 ppma, that is, 0.5 × 1015 cm 3 at cryogenic temperatures (below 80 K).
 

This Test Method utilizes the relationship between carbon concentration and the absorption coefficient of the infrared absorption band associated with substitutional carbon in silicon. At room temperatures (about 300 K), the absorption band peak is at 605 cm1 or 16.53 µm. At cryogenic temperatures (below 80 K), the absorption band peak is at 607.5 cm1 or 16.46 µm.
 

This Test Method is applicable to slices of silicon with resistivity higher than 3 ·cm for p-type and higher than 1 ·cm for n-type. Slices can be any crystallographic orientation and should be polished on both surfaces.
 

This Test Method is intended to be used with infrared spectrophotometers that are equipped to operate in the region from 2000 cm1 to 500 cm1 (5 µm to 20 µm).
 

This Test Method provides procedure and calculation sections for the cases where thickness values of test and reference specimens are both closely and not closely matched.

Referenced SEMI Standards (purchase separately)
SEMI M59 — Terminology for Silicon Technology

Revision History
SEMI MF1391-1107 (Reapproved 1023)
SEMI MF1391-1107 (Reapproved 0912)
SEMI MF1391-1107 (technical revision)
SEMI MF1391-0704 (technical revision)
SEMI MF1391-93 (Reapproved 2000) (first SEMI publication)