High-speed μc-Si films deposition and large-grain poly-Si films deposition by surface wave discharge

Microcrystalline silicon (gc-Si) and polycrystalline silicon (poly-Si) films are deposited by surface wave (SW) discharge at 2.45 GHz in H-2/SiH4 gas. This high density SW plasma at relatively low pressures (4-60 Pa) enables strong dissociation of feedstock gas. The films deposited on substrate are investigated by X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). The SW discharge in 10% SiH4 at total pressure of similar to 30 Pa gives mu c-Si films on a substrate at 250 degrees C, at a fairly high deposition rate of 4-20 nm/s, with a crystalline volume fraction of 0.5-0.8 and a grain size of 10-40 nm. Furthermore, poly-Si film with crystalline volume fraction of > 99% is deposited at higher substrate temperature (400 degrees C) in 2% SiH4 discharge at lower pressure (4 Pa). X-ray diffraction and SEM results revealed that the grain size of poly-Si films is as large as 600 nm, which is almost 6 times larger than previously reported values. (c) 2006 Elsevier B.V. All rights reserved.