samples are heated from a room temperature to about 1000 u00b0 c by means of a tds analysis device and amounts of impurities undergone desorption from the samples are quantified thereafter in fig6 a and 6b both vertical axes represent a desorption flux of the impurities while both horizontal axes represent temperature herein the vertical axes are expressed in a linear scale and measured in a u with reference to fig6 a and 6b in case of comparing the measured results obtained at a temperature around 200 u00b0 c an amount of h 2 desorption in the first sample is approximately 15000 a u on the other hand an amount of h 2 desorption in the second sample is approximately 25000 a u in addition an amount of co 2 desorption in the first sample is below approximately 10000 a u however an amount of co 2 desorption is approximately 30000 a u also an amount of desorption of m 28 e g co and c 2 h 4 is approximately 8000 a u in the first sample whereas an amount of desorption of m 28 is approximately 25000 a u in the second sample according to the above measured result the ru film deposited in accordance with the cvd process using the nh 3 as the reaction gas contains less amounts.