Analysis of gallium arsenide by spark-source mass-spectrometry.
A method has been developed for analysing gallium arsenide with a resistance of greater than 10(9)Omega by spark-source mass-spectrometry, without the need for pelleting, which introduces a prohibitively high level of contamination and lowers the detection limit for a given exposure. It uses a gold evaporation technique, whereby a thin layer of 99.999% pure gold is deposited on one surface of the GaAs electrodes, in a chamber mounted on the ion-source. No contamination, other than gold, is introduced into the sample at a level of 50 ng/g or greater. It is possible to detect carbon in the sample at the 1-2 mug/g level. The sample preparation time is less than 30 min, and more than one set of samples can be gold-coated at a time.
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GTE Laboratories Incorporated, Waltham, MA 02254, U.S.A.