Determination of boron in silicon-doped gallium arsenide by electrothermal atomic absorption spectrometry and ultraviolet-visible spectrophotometry.
Two methods have been developed for the determination of boron impurities in silicon-doped gallium arsenide (GaAs) for electronics. The first method employs the electrothermal atomic absorption spectrometry (ETAAS), the second, the UV-Vis molecular absorption spectrophotomety. In both cases the GaAs sample is decomposed with aqua regia (1+1). To prevent Ga(III) interference on the ETAAS determination of boron, a double extraction of the chlorogallic acid (HGaCl4) in diethyl ether is performed. To improve the overall ETAAS performance, the graphite tubes were pre-treated with iridium(III) and tungsten(IV). A mixed chemical modifier containing Ni(II), Sr(II) and citric acid was also used. The characteristic mass (m0) is 301 +/- 47 pg and the detection limit (3sB) is 2.4 microg g(-1). The classic UV-Vis spectrophotometric procedure using curcumin was also extended to the determination of boron in GaAs. By masking Ga(III) with EDTA and a preliminary extraction of boron with 2-ethyl-hexane 1,3-diol, performed on a semi-micro scale, a detection limit of 0.6 microg g(-1) was achieved. Both methods were applied to the analysis of two Si-doped GaAs samples which were suspected of being boron-contaminated. Results are compared with those obtained by direct analysis of the decomposed sample solution using the inductively coupled plasma atomic emission spectrometry (ICP-AES).
Taddia
Marco
M
Dipartimento di Chimica G. Ciamician, Università di Bologna, Via F. Selmi 2, 40126 Bologna. taddia@ciam.unibo.it
Cerroni
Maria Grazia
MG
Morelli
Elio
E
Musiani
Andrea
A
D001152:Arsenicals / Q000032:analysis*; D001895:Boron / Q000032:analysis*; D004581:Electronics; D004784:Environmental Monitoring / Q000379:methods; D005708:Gallium / Q000032:analysis*; D006801:Humans; D012825:Silicon; D013054:Spectrophotometry, Atomic / Q000379:methods; D013056:Spectrophotometry, Ultraviolet / Q000379:methods
D001152:Arsenicals; C043055:gallium arsenide; D005708:Gallium; D001895:Boron; D012825:Silicon