EFFECT OF CARBON ON THERMAL-OXIDATION OF SILICON AND ELECTRICAL-PROPERTIES OF SIO2-SI STRUCTURES

Growth of thermal oxide on silicon implanted with carbon at low energies is studied and electrical characteristics of the resulting SiO2-Si structures are evaluated. After excluding the effect of surface damage on the oxide growth kinetics, it was determined that for the carbon implant doses up to 10(14) cm-2 the effect on oxide growth kinetics is limited. At higher carbon doses significant retardation of oxide growth was observed. A clear correlation between carbon dose and electrical characteristics of SiO2-Si structures has also been established. In the case of each parameter of concern in this study its degradation with increased carbon dose above 10(14) cm-2, which corresponds to carbon concentration in silicon of the order of 10(19) cm-3, was observed. These effects may come to play during thermal oxidation of silicon wafers subjected prior to oxidation to the reactive ion etching in carbon containing gases such as CF4, CHF3, and others.