FABRICATION OF DIAMOND TUBES IN BIAS-ENHANCED HOT-FILAMENT CHEMICAL VAPOR DEPOSITION SYSTEM

Deposition of diamond thin films on tungsten wire substrate with the gas mixture of ace- tone and hydrogen by using bias-enhanced hot filament chemical vapor deposition(CVD)with the tantalum wires being optimized arranged is investigated.The self-supported diamond tubes are ob- tained by etching away the tungsten substrates.The quality of the diamond film before and after the removal of substrates is observed by scanning electron microscope(SEM)and Raman spectrum.The results show that the cylindrical diamond tubes with good quality and uniform thickness are obtained on tungsten wires by using bias enhanced hot filament CVD.The compressive stress in diamond film formed during the deposition is released after the substrate etches away by mixture of HOand NHOH.There is no residual stress in diamond tube after substrate removal.