Low pressure CVD for wide area diamond film deposition at low temperature

We have applied magneto-microwave plasma to be successful, for the first time, in deposition of diamond at far lower pressure than the conventional high pressure plasma CVD. The important point of the low pressure plasma deposition system is to set the electron cyclotron resonance (ECR) condition (875 G in the case of a 2.45 GHz microwave) at the deposition area. The high density plasma (above 1×10¹¹ /cm³) necessary for high quality diamond formation has been obtained by the effective microwave absorption near the magnetic field satisfying the ECR condition. The plasma is quite uniform at the discharge area (160 mm in diameter) and uniform diamond films with high quality have been obtained. From the investigation of diamond formation from 50 Torr to 10^-2 Torr in the same deposition system, it is definite that the lower pressure lowers the formation temperature of diamond to 500°C and the effective species for diamond formation are low energy radicals.