Effect of hydrogen dilution on the growth of nanocrystalline silicon films at high temperature by using plasma-enhanced chemical vapor deposition

Two hundred-nm-thick nanocrystalline silicon films were deposited at 620 degreesC under different H-2 flow rates, ([H-2]), by plasma-enhanced chemical vapor deposition using SiH4/H-2 mixtures. When [H-2] increased, the grain size decreased. On the other hand, no crystallization was found at [H-2] = 5 seem. The photoluminescence spectra changed from a single peak of approximately 2.0-2.1 eV at [H-2] = 10 sccm to two separated lines of approximately 1.7 and 2.1 eV at [H-2] between 15 and 20 sccm. However, the 2.1-eV band decreased with increasing [H-2], and at [H-2] = 25 sccm, we observed a single peak at approximately 1.8 ev The hydrogen content decreased and two infrared absorption bands approximately at 850 and 1000 cm(-1) also decreased with [H-2]. (C) 2003 Elsevier Science B.V. All rights reserved.