基体偏压对HiPIMS制备非晶碳膜结构和光电性能的影响

Influence of Substrate Bias on Microstructure, Optical-and Electrical-Properties of Amorphous-Carbon Films Prepared by High Power Pulse Magnetron Sputtering

采用高功率脉冲磁控溅射(Hi PIMS)工艺在单晶硅和石英基体上沉积a-C膜,研究了基体偏压对其结构和光电性能的影响。结果表明,基体偏压的变化能显著改变薄膜的微观结构。在偏压为0^-300 V条件下制备的a-C膜,sp^2的含量均为(52.5±1.5)%,基本不变。偏压为-50 V时sp^2团簇的尺寸达到最大值(约1.93 nm),薄膜的光学带隙(0.15 e V)和电阻率(0.32Ω·cm)达到最小值;偏压继续提高则sp^2团簇的尺寸先减小后增加,光学带隙和电阻率先增加后减小,符合非晶碳膜的团簇模型。HiPIMS工艺制备的非晶碳薄膜,其sp^2团簇的尺寸决定了薄膜光学和电性学能。薄膜sp^2团簇尺寸越大,则光学带隙和电阻率越小。

The effect of substrate bias voltages on the microstructure, optical-and electrical- proper- ties of a-C films prepared by HiPIMS were investigated on silicon wafers and quartz glass respectively. Results show that different substrate biases lead to the change of microstructure of the a-C films. The sp2 content of a-C film prepared at bias of 0～-300 V is （52.5＋1.5）%. When the voltage was -50 V, the size of sp2 cluster reached the maximum （1.93 nm）, yet the optical band gap （0.15 eV） and resistivity （0.32Ωcm） were minimum. Then the size of sp2 cluster decreased first and then increased with the increase of biasvoltage, while the optical band gap and resistance of the films presented opposite tendency according to the cluster model. The size of sp2 clusters in a-C films by HiPIMS played the key role in the optical and electrical properties. The larger the size of the film sp2 cluster was, the smaller optical band gap and resis- tivity were.