OXIDATION OF SILICON IN AN ELECTRON-CYCLOTRON RESONANCE OXYGEN PLASMA - KINETICS, PHYSICOCHEMICAL, AND ELECTRICAL-PROPERTIES

An electron cyclotron resonance (ECR) plasma system was used to oxidize single-crystal silicon. Two distinct oxidation processes were observed, one of which was ion flux controlled. Oxidation of trench structures confirmed the existence of these two oxidation regimes. Kinetic rate studies indicated that the effective activation energies for both oxidation processes were substantially lower than the activation energy of atmospheric pressure steam or dry oxygen oxidation. The Deal-Grove linear-parabolic rate law can be used to describe long-time ion-controlled oxidation rates, although the theory of Wolters-Zegers-van Duynhoven best described the observed oxidation rates. Oxides grown in the ion flux controlled regime had growth rates and physicochemical properties nearly identical to thermal oxides grown at atmospheric pressure and above 1123 K, whereas oxides grown outside this regime were self-limiting (~10G A) in thickness and of poorer dielectric quality unless subjected to a post oxidation anneal. Capacitance-voltage (C-V) and current-voltage (I~F) studies indicated that the fixed charge density was — 1X 10ncm2and that the average breakdown strength over a 3 in. wafer was approximately 7 MV cm1. © 1990, American Vacuum Society. All rights reserved.