Effect of GeF{sub}4 addition on the growth of hydrogenated microcrystalline silicon film by plasma-enhanced chemical vapor deposition

摘要

The effects of the addition of germanium tetrafluoride, GeF{sub}4, are demonstrated on the growth of films of hydrogenated microcrystalline silicon, μc-Si:H, from SiH{sub}4 and H{sub}2 by r.f. plasma-enhanced chemical vapor deposition (r.f.PECVD). The structural and optoelectrical properties of theμc-Si(Ge):R(F) film are examined as a function of the flow rates of GeF{sub}4 and H{sub}2. The addition of GeF{sub}4 enhances the deposition rate and the crystallinity of the Si network, when the flow rate ratio, r=Fr(GeF{sub}4)/Fr(SiH{sub}4) is below 10. On the other hand, under conditions, r>0.1, the formation of a SiGe{sub}x crystalline phase is promoted. The combination of the flow rates of GeF{sub}4 and H{sub}2 greatly affects theenhancement of crystallinity along with an increase in surface roughness.