Investigation of the microwave electromagnetic field attenuation effect in the discharge chamber of a resonant type plasmatron

Abstract

The investigation of the microwave energy penetration (f = 2,45 ± 0,05 GHz) in the center of the oxygen gas discharge in the resonant type plasmatron was carried out on the example of microwave plasma-chemical processing of silicon plates. The investigation was performed by three independent methods: using a thermocouple for investigating temperature characteristics of the microwave discharge; according to the data of the "active probe" which was injected into the volume of discharge chamber; using an electric probe which was placed in the volume of plasma for measuring the electrical conductivity of the space. The experimental results indicate that for the levels of microwave power flux density in the discharge volume ranging within 0.06-0.08 W/cm3 the microwave field is entered into the volume of the discharge zone. This effect must be taken into account when organizing the processes of plasma-chemical treatment (the influence of microwave field on the parameters of the processed structures, explanation of "loading effect", when chosen construction of a system for supplying microwave energy to the treatment area, in the analysis forms and character of microwave field distribution in the gas discharge area, etc.) and for analysing the results of processing of materials and semiconductor structures which may be exposed to microwave energy.