Oxygen implantation and diffusion in pure titanium by an rf inductively coupled plasma

Abstract: The superficial oxidation of pure titanium, 9mm diameter, 5mm thick disc samples by implantation and diffusion from inductively coupled plasmas is reported. Such rf plasmas were generated in a 15l cylindrical Pyrex-like glass chamber containing pure circulating oxygen. A quarter wavelength solenoidal antenna capable of transmitting 500W at 13.54MHz was externally wound around the chamber and connected to an rf generator capable of up to 1200W through an automatic matching network. The oxidation process was carried out for 6h periods while varying the gas pressure between 1×102 and 5×10−1 Pa and the sample bias up to −3000V DC. It was found that the sample temperature was a function both of the plasma density and the bias voltage. Without bias, the plasma heated the sample up to ∼200°C, and with maximal bias voltage, the substrate was heated to 680°C. At the latter temperature, the presence of the rutile phase was particularly evident in X-ray diffraction patterns. According to EDX data, the average oxygen to titanium ratio rose, from ∼0.06 for an untreated reference sample, to a ∼1.7 value for samples treated up to 680°C. [Copyright &y& Elsevier]