The deposition and study of hard carbon films

Abstract

Carbon films have been deposited by rf plasma decomposition of methane at 50–1400 V negative bias and 1.3×10⁻³–1.3×10⁻¹ mbar pressure. Hardness, internal stress, density, hydrogen content, and infrared absorption depending on the preparation parameters have been measured. From the IR measurements the ratio of sp³ to sp² bonds was calculated and the total amount of hydrogen in the films was determined by elastic recoil detection (0.5>H/C>0.15). We found in the range of bias voltages 0<‖−V_B ‖V_B ‖V_B ‖3 and of the graphitelike films about 1.4 g/cm³. The microhardness seems to be correlated to the internal mechanical stress.