Evaluation of departure from stoichiometry of gallium arsenide crystals

Abstract

A method is described for determining arsenic in gallium arsenide. In order to avoid the conventional pre-reduction process, arsenic is directly titrated iodimetrically as As(V) in acidic solution. The determination is made with an automatic titrator and potentiometric detection of the equivalent point. Pure arsenic is used as a reference substance. Deviations from the stoichiometric composition of the order of 10 −3-10 −4% with a standard deviation of about 0.06% can be determined. The limits of chemical analysis for controlling the stoichiometry of the semiconductor are discussed.