Investigating the Effect of Process Parameter on the Properties of Rf Sputtered pSi Thin Film by Taguchi and ANOVA Analysis

Boron doped pSi was deposited on Si substrate in the RF magnetron sputtering system by varying three process parameters, namely-sputtering power, working pressure, and Ar gas flow rate. Subsequently, the effect of these process parameter changes on the surface (roughness, morphology), structural (crystallography, grain size, micro-stress), and electrical (resistance and capacitance per unit area) properties were investigated using Taguchi Signal-to-noise (S/N) analysis and Analysis of Variance (ANOVA). Three sets of inputs for the three mentioned process parameters were chosen to sputter the thin films. The levels were: for power- 100, 150 & 200 Watts, for pressure- 10, 15 & 20 mTorr, and for Ar flow rate- 5, 10 & 15 sccm. By performing Taguchi L 9 orthogonal array, nine samples of pSi thin films were fabricated. Signal to noise ratio (S/N) tells how a particular property is affected by the process parameters variation, while ANOVA statistical analysis determines the contributions of each process parameter on the change of that particular property. Our experimental result showed that sputtering power plays the most influential role in the properties of pSi thin films among the three chosen parameters. The impact of working pressure is also very significant. Ar gas flow rate, on the other hand, has minimal effect on the thin film properties.