Effect of Buffer Gas on Generation of KrF* Excimer Using Silent Discharge

Excimer sources which emit UV or VUV ray in the energy range of 5-10eV have a number of interesting applications. Especially, it is expected to apply photochemical reactions, for example, the photolytic deposition on semiconductor, because they are possible to cut most chemical bonds without any thermal reaction. Recently excimer lamp is paid attention to use at the large area surface modification.In the case of excimer lasers, He, Ne or He/Ne diluent are generally used as a buffer gas for forming inverted population and stable laser operation. On the other hand, buffer gas plays an important role on excimer generation via three body reaction. As a silent discharge holds back to turn into an arc discharge, it is expected that dominant effect of buffer gas will be shown on excimer generation via three body reaction.In this paper, effect of buffer gas on excimer generation is studied using some rare gases (Ar, He, Ne and Kr) as a diluent. As a result, intense excimer KrF* radiation was observed in Ar or Kr diluent. For this reason, energy level in buffer gases is important factor on excimer generation. Then, it is concluded that contribution on excimer formation of buffer gas is mainly absorption of surplus energy on three body reaction.