High-vacuum carbosilicothermic reduction of manganese in thin films

High-vacuum carbosilicothermic reduction of MnO_x thin films on Si(100) substrates was investigated in the temperature range of 200–700 °C using in-situ Auger electron spectroscopy along with mass spectroscopy and ex-situ X-ray photoelectron spectroscopy. Carbothermic reduction of manganese, accompanied by the CO evolution, occurs over the entire temperature range. When heated above 500 °C, silicothermic reduction and formation of manganese silicides are observed. The efficiency of carbothermic reduction of Mn in thin films turned out to be higher at C:Mn = 1:10 than at C:Mn = 1:5. Carbon in the samples is assumed to be present in two forms: as amorphous carbon in a mixture with oxygen and manganese, and as individual, larger particles with a graphite structure. The particle size depends on the power of the magnetron source and influences the carbon coalescence activity, which competes with the carbothermic reduction process. The efficiency of silicothermic reduction on the film surface depends on the initial carbon concentration.