Multitarget sputtering using decoupled plasmas

Abstract

A method is developed for quantitatively predicting the chemical composition and thickness distributions of alloy films deposited by decoupled‐plasma multitarget rf sputtering in which the substrates rotate at a variable rate through separate glow discharges. The film thickness distributions deposited from each target are expressed in terms of deposition variables such as applied target voltage, target radius, sputtering pressure, substrate rotation radius, rotation rate, and target‐substrate separation. Predicted films thickness distributions were found to be in agreement with experimental results in which β backscattering was used to measure the thickness of InSb films deposited on both stationary and rotating substrates. Using deposition parameters determined from the model presented in this paper, single‐phase In_1−xGa_xSb alloy films were grown whose experimentally determined compositions agreed with predicted values. Intercalated films with layer thicknesses of less than 100 Å and films which were chemically graded in the lateral and in‐depth directions were also grown.