Spark source mass spectrometric calibration of the local vibrational mode absorption of carbon in gallium arsenide on arsenic sublattice sites

Abstract

An appropriate calibration of the local vibrational mode absorption of carbon in GaAs on arsenic sublattice sites, CAs, at wavenumber 582 cm–1 (77 K) is presented. Integrated absorptions Iα of CAs, the dominant acceptor in undoped monocrystalline GaAs, and calibrated carbon concentrations [C] were measured in single crystals using the methods FTIR and SSMS, respectively. A calibration factor fC = [C]/Iα of (7.1 ± 0.2) × 1015 cm–1 has been derived for 2.8 × 1014 cm–3≤ [C] ≤ 1.4 × 1016 cm–3 above a SSMS detection limit of [C]DL≅ 1.4 × 1013 cm–3. The carbon concentrations [C] = [C]SSMS/RSCC were calibrated with a relative sensitivity coefficient RSCC = [C]SSMS/ [C]TRUE of 3.1 ± 0.1. CPAA was used as a reference method for [C]CPAA≥ 4.4 × 1014 cm–3 in order to approximate [C]TRUE.