Deposition of Tungsten Films by Pulsed Excimer Laser Ablation Technique

Low temperature deposition of W on Semiconductor substrates is vital for microelectronics technology. Laser ablation technique using KrF (248 nm) excimer laser has been employed to deposit W films from W(CO)6. The substrates used are Si(100) and SiO2. The influence of substrate temperature on the film growth rate was investigated in a broad temperature range (20 - 500 °C), keeping the laser fluence fixed at 0.4 Jcm−2. The substrate temperature is found to have a strong influence on the resistivity of the deposited films. Film resistivities within a factor of 3 of the value for pure bulk W have been observed in the substrate temperature range of 300 - 500 °C. X-ray diffraction data were also obtained. These revealed that the crystal structure of the film deposited in this temperature range corresponds specifically to the m-phase. Optical emissions from the plasma generated during the pulsed excimer laser ablation of W(CO)6 are also examined by an optical Multichannel Analyser (OMA).