In situ hydrogen plasma treatment for improved transport of (400) oriented polycrystalline silicon films

Polycrystalline silicon (poly-Si) films were deposited on glass by very high-frequency (100 MHz) plasma enhanced chemical vapor deposition from a gaseous mixture of SiF4 and H-2 with small amounts of SiH4. (220) oriented films prepared at small SiF4/H-2 ratios ( < 30/40 seem) showed intrinsic transport properties of poly-Si. However, the room temperature dark conductivity (<sigma>(d)) of the (400) oriented film was very high for intrinsic poly-Si, 7.2 x 10(-4) S/cm. This conductivity exhibited a T-1/4 behavior, suggesting a high defect density at the grain boundaries. It was found that in situ hydrogen plasma treatment successfully produced (400) oriented poly-Si with a reasonably low sigma (d) of 4.5 x 10(-7) S/cm and a good photoconductivity of 1.3 x 10(-4)S/cm. (C) 2001 Elsevier Science B.V. All rights reserved.