沉积功率对多晶硅薄膜结构和光学性质的影响

Influence of RF Power on Structure and Optical Properties of Polycrystalline Silicon Thin Films

采用等离子体化学汽相沉积（PECVD）方法在普通玻璃衬底上制备出多晶硅薄膜。研究了在不同沉积功率下的薄膜的沉积速率、晶相结构、吸收系数和光学禁带宽度。实验结果表明，沉积功率为140W时薄膜沉积速率最大，达到7．8nm／min。沉积功率为30W多晶硅薄膜的晶粒较大，平均尺寸200nm左右。沉积功率为100W薄膜有较高结晶度，晶化率达到68％。薄膜样品在波长为500nm的光吸收系数达到6×10^4cm^-1，在不同功率下样品的光学禁带宽度在1．70—1．85eV之间变化。

Polycrystalline silicon thin film was fabricated by plasma enhanced chemical vapor deposition on glass substrate. The deposition rate, crystalline microstructure, absorption coefficient and optical bandgap of the film were studied at different RF power. It indicated that the deposition rate increases linearly with increase of RF power; low RF power 30 W corresponded to the large size of crystalline grain of 200 nm; the thin film has the best crystalline fraction of 68% at RF power 100 W; the absorption coefficient of the films increases with increasing of RF power; the optical bandgap changed between 1.70 eV and 1. 85 eV at different RF power.