Characterization of Amorphous Hydrogenated Carbon Formed by Low-Pressure Inductively Coupled Plasma Enhanced Chemical Vapor Deposition Using Multiple Low-Inductance Antenna Units

摘要

Three-dimensional plasma enhanced chemical vapor deposition (CVD) of hydrogenated amorphous carbon (a-C:H) has been demonstrated using a new type high-density volumetric plasma source with multiple low-inductance antenna system.The plasma density in the volume of phi 200 mm x 100 mm is 5.1 x 10~(10) cm~(-3) within +-5% in the lateral directions and 5.2 x 10~(10)cm~(-3) within +-10% in the axial direction for argon plasma under the pressure of 0.1 Pa and the total power as low as 400 W.The uniformity of the thickness and refractive index is within +-3.5% and +-1%,respectively,for the a-C:H films deposited on the substrates placed on the six side walls,the top of the phi60 mm x 80 mm hexagonal substrate holder in the pure toluene plasma under the pressure is as low as 0.04 Pa,and the total power is as low as 300 W.It is also found that precisely controlled ion bombardment by pulse biasing led to the explicit observation in Raman and IR spectra of the transition from polymer-like structure to diamond-like structure accompanied by dehydrogenation due to ion bombardment.Moreover,it is also concluded that the pulse biasing technique is effective for stress reduction without a significant degradation of hardness.The stress of 0.6 GPa and the hardness of 15 GPa have been obtained for 2.0mum thick films deposited with the optimized deposition conditions.The films are durable for the tribology test with a high load of 20 N up to more than 20 000 cycles,showing the specific wear rate and the friction coefficient were 1.2 x 10~(-7) mm~3/Nm and 0.04,respectively.