Influence of the parameters of plasma enhanced chemical vapor deposition (PECVD)on the surface morphology of hydrogenated amorphous silicon (α-Si:H) film was investigated. Theroot-mean-square (RMS) roughness of the film was measured by atomic force microscope (AFM)and the relevant results were analyzed using the surface smoothing mechanism of film deposition.It is shown that an α-Si:H film with smooth surface morphology can be obtained by increasingthe PH_3/N_2 gas flow-rate for 10% in a high frequency (HF) mode. For high power, however, thesurface morphology of the film will deteriorate when the SiH_4 gas flow rate increases. Furthermore,optimized parameters of PECVD for growing the film with smooth surface were obtained to beSiH_4: 25 sccm (standard cubic centimeters per minute), Ar: 275 sccm, 10%PH_3/N_2:2 sccm, HFpower: 15 W, pressure: 0.9 Torr and temperature: 350℃. In addition, for in thick film depositionon silicon substrate, a N_2O and NH_3 preprocessing method is proposed to suppress the formationof gas bubbles.
