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

Abstract Two hundred-nm-thick nanocrystalline silicon films were deposited at 620 °C under different H 2 flow rates, ([H 2 ]), by plasma-enhanced chemical vapor deposition using SiH 4 /H 2 mixtures. When [H 2 ] increased, the grain size decreased. On the other hand, no crystallization was found at [H 2 ]=5 sccm. 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 ].