Hydrogenated microcrystalline silicon (μc-Si:H) films are prepared by hot-wire assisted plasma enhanced chemical vapor deposition, which controls the hydrogen radical density by filament temperatures, Tf, without changing other conditions. The effect of hydrogen radical on the properties of incorporated hydrogen into μc-Si:H films is studied using infrared absorption and gas effusion spectroscopies. The hydrogen concentration decreases with increasing Tf. The crystalline volume fraction, Xc, increases with Tf and shows a peak at Tf of 1850 °C. Integrated intensities of the modes near 2000 and 2100 cm-1 decrease with increasing Tf. Integrated intensity of the mode near 880 cm-1 shows almost same tendency of Xc. The effect of hydrogen radical on the properties of incorporated hydrogen into μc-Si:H films is discussed.

Higher crystalline Si volume fractions in hydrogenated microcrystalline silicon ( µc-Si:H) films have been achieved by the hot-wire assisted plasma enhanced chemical vapor deposition (HWA-PECVD) method compared with those in films by conventional PECVD. µc-Si:H films can also be prepared by HWA-PECVD under typical conditions used for preparing hydrogenated amorphous silicon (a-Si:H) films by PECVD, in which the hydrogen-dilution ratio (H2 / SiH4) is ∼ 10. The hot wire seems to produce hydrogen radicals. As a result, the HWA- PECVD method can control hydrogen-radical densities in the RF plasma, and this method can also control the ratio of hydrogen coverage at the surface of the film.

An innovative bending-beam method is used to study the stress of thin film a-Si:H deposited on thin quartz by hot-wire chemical vapor deposition (CVD) techniques. When the deposition temperature increases from 280 to 440 °C the hydrogen content decreases from 8 to <1 at.%, and the initial compressive stress also decreases from 420 to 74 MPa. We found that there is a 10−4 photo-induced increase of the initial compressive stress under 300 mW/cm2 light-soaking, which can be recovered to the initial value by thermal annealing at 160 °C for 1 h. The results imply that the Si-H bonds contribute to the compressive stress in the a-Si:H film. There is no simple correlation between the stress and the photodegradation of the electronic properties.

In the optical reflectance spectrum of the random multilayers of a-Si:H/a-Si3N4+x:H, it is observed an anomalous peak which is explained by the classical localization of light propagation. The following two subjects are discussed in this report; (a). The Kramers-Kronig transformation is done including the anomalous disorder-related reflectance peak. Extra absorption coefficients Δα are obtained by this analysis. Energy dependence of the localization length 1(hv) of light propagation are obtained by 1(hv)=1/Δα(hv). (b). The other is the experiment on scaling where the ratio of the disorder and the average layer thickness is kept constant but the size of each layer is changed in each experiment