Radiation and hot-electron hardness of SiO2/Si grown in O2 with trichloroethane additive

The effects of 1,1,1,-trichloroethane (TCA) in the silicon thermal oxidation environment on the hardness of the resulting SiO₂/Si structures to damages caused by ionizing radiation and hot electron injection have been investigated. Using small amounts of TCA during the initial stage of oxidation, it is possible to improve the hardness of the interface. When excess amounts of TCA are used, however, the hardness degrades. In the range typically used in industry, the hardness goes down monotonically with increasing amount of TCA. The use of TCA also causes a significant change in the gate-size dependence of the radiation or hot electron induced interface traps. This dependence is almost completely suppressed in devices where maximum hardness of the oxide is achieved by optimizing the amount of TCA. These results are examined in terms of the effects of Cl on the interfacial strain near the SiO₂/Si transition region