Low temperature growth of polycrystalline semiconductor and diamond films

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In order to make polycrystalline silicon films at low temperature, hydrogen radicals have been utilized in the rf sputtering process. The films were prepared in gas mixtures containing argon and hydrogen. They were investigated by reflection electron diffraction and Raman spectroscopy. Furthermore, optical emission spectroscopy was employed to study the quantity of hydrogen radicals in the plasma, and the plasma potential was measured to decide the substrate bias voltage under realistic plasma condition for the deposition of silicon films.The results showed that polycrystalline silicon films were grown even at the substrate temperature of less than 200ﾟC.It was also found from the optical emission spectroscopy that there existed atomic hydrogen radicals with high energy of about 10eV.They are expected to be able to restructure the silicon atoms on the substrate. Thus the crystallization at such low temperature is considered to be mainly due to hydrogen radicals in the plasma.Structure … More of polycrystalline silicon films was investigated by X-ray diffraction, reflection electron diffraction and transmission electron microscopy. Furthermore, electrical and optical properties of the films were studied with the measurements of IR absorption, optical absorption, electron spin reesonance and electrical conductivity. The films were prepared by rf planar magnetron sputtering, in which process atomic hydrogen radicals were utilized in order to make the polycrystalline silicon films on the substarate at low temperature. Its was shown from X-ray diffraction, reflection electron diffraction and transmission electron microscopy that most of crystal silicon grains grew with a [100] texture, and that the grain sizes were 10--20'nm.The results obtained from IR absorption and optical absorption measurements were as follows ; hydrogen content decreased with the increase of hydrogen partial pressure (P_<H2>) in the range of 2<=P_<H2><=7mTorr, which was caused by the formation of Si--Si bonds, and in the range of 7<=P_<H2><=12mTorr, however, hydrogen content increased gradually with P_<H2>, which suggested that dangling bonds in the silicon films were more terminated in the higher hydrogen partial pressure. These facts were also explained by the electrical conductivity measurement, and it was found that the polycrystalline silicon film prepared under the highest hydrogen partial pressure had the lowest hopping site density in the films observed in this work. Less