Synthesis of highly conductive boron-doped p-type hydrogenated microcrystalline silicon (mu c-Si : H)by a hot-wire chemical vapor deposition (HWCVD) technique

Boron-doped hydrogenated microcrystalline silicon (mu c-Si:K) films were pr epared using hot-wire chemical vapor deposition (HWCVD) technique. Structur al, electrical and optical properties of these thin films were systematical ly studied as a function of B2H6 gas (diborane) phase ratio (Variation in B 2H6 gas phase ratio, dopant gas being diluted in hydrogen, affected the fil m properties through variation in doping level and hydrogen dilution). Char acterization of these films from low angle X-ray diffraction and Raman spec troscopy revealed that the high conductive film consists of mixed phase of microcrystalline silicon embedded in an amorphous network. Even a small inc rease in hydrogen dilution showed marked effect on film microstructure. At the optimized deposition conditions, films with high dark conductivity (0.0 8 (Omega cm)(-1)) with low charge carrier activation energy (0.025 eV) and low optical absorption coefficient with high optical band gap (similar to 2 .0 eV) were obtained. At these deposition conditions, however, the growth r ate was small(6 Angstrom/s) and hydrogen content was large (9 at%). (C) 200 0 Elsevier Science B.V. All rights reserved.