SEMI M82 - Test Method for the Carbon Acceptor Concentration in Semi-Insulating Gallium Arsenide Single Crystals by Infrared Absorption Spectroscopy -

Abstract

1 Purpose
1.1 The purpose of this Document is to specify a method for the measurement of the carbon acceptor concentration in semi-insulating (SI) gallium arsenide (GaAs) by infrared absorption.
2 Scope
2.1 This Test Method covers the determination of the carbon content in GaAs using infrared (IR) absorption. The test method utilizes the linear relationship between the carbon content and the integrated absorption of the localized vibration of substitutionally bonded carbon (CAs). At a measurement temperature of 300 K (room temperature) this absorption band is observed at 580 cm−1, at 77 K between 582 cm−1 and 583 cm−1.
2.2 This Test Method covers the determination of substitute carbon mainly in SI single crystal GaAs. It may also be used for polycrystalline GaAs and conducting GaAs up to a free carrier concentration of about 1 × 1016 cm−3.
2.3 This Test Method is applicable for carbon content between 1 × 1013 cm−3 and the solubility limit (>1 × 1016 cm−3). The lower limit depends on the measurement temperature, the sample geometry and the quality of the spectrometer.
2.4 Measurement temperatures of both 300 K and 77 K may be used.
2.4.1 Advantages of the 300 K measurement are:
• the required spectral resolution is 1 cm-1 as compared to 0.1 cm−1 or 0.5 cm−1 at 77 K;
• cryostat is not necessary.
2.4.2 Advantages of the 77 K measurement are:
• sensitivity is higher (and therefore the detection limit lower);
• no reference sample with a low carbon content is necessary;
• commercial thin wafers can be measured.
2.5 The chemical carbon content in GaAs may be higher than the substitute carbon content CAs as measured by this Test Method. According to the present knowledge, however, state-of-the-art single crystal GaAs contains CAs only.
2.6 This Document follows the roadmap laid out by SEMI M54, defining the carbon concentration as an essential material parameter.
NOTICE: SEMI Standards and Safety Guidelines do not purport to address all safety issues associated with their use. It is the responsibility of the users of the Documents to establish appropriate safety and health practices, and determine the applicability of regulatory or other limitations prior to use.

Referenced SEMI Standards (purchase separately)
SEMI M54 — Guide for Semi-Insulating (SI) GaAs Material Parameters
SEMI M64 — Test Method for the EL2 Deep Donor Concentration in Semi-Insulating (SI) Gallium Arsenide Single Crystals by Infrared Absorption Spectroscopy
NOTICE: Unless otherwise indicated, all documents cited shall be the latest published versions.

Revision History
SEMI M82-0820 (Reapproved 0826)
SEMI M82-0820 (technical revision)
SEMI M82-0813 (technical revision)
SEMI M82-0712 (first published)

Interested in purchasing additional SEMI Standards? Consider SEMIViews, an online portal with access to over 1000 Standards.

Refund Policy: Due to the nature of our products, SEMI has a no refund/no exchange policy. Please make sure that you have reviewed your order prior to finalizing your purchase. All sales are final.