Pregate Oxidation Treatment using Radio Frequency Activated Nitrogen in a Rapid Thermal Reactor

A rapid thermal treatment in nitrogen could be inserted immediately before the gate oxidation step in a typical process flow for making metal-oxide-semiconductor field effect transistors. The treatment, performed in a radio frequency induction heated singlewafer rapid thermal reactor, is used to reduce the subsequent oxidation rate and to incorporate nitrogen in the resulting gate dielectrics. It is believed that activated molecular or atomic nitrogen is generated in the rapid thermal reactor and is responsible for the slight nitridalion of the exposed silicon area during the rapid thermal treatment. Potential radiation damage to the silicon area is minimized by activating the nitrogen remotely from the wafer chamber. The effects of the nitrogen flow rate and the temperature during the treatment process on the kinetics of the subsequent oxidation in a regular furnace and the chemical composition of the resulting gate dielectrics are studied. Potential use of the proposed treatment in making scaled devices is discussed.