Structure Change of Microcrystalline Silicon Films in Deposition Process

Abstract

Structure change with thickness of films of microcrystalline silicon prepared by reactive sputtering and glow discharge techniques has been investigated with transmission electron microscopes and a Fourier transform infrared spectrophotometer. An amorphous state changes into a microcrystalline one with increase of the thickness from 10 to 100 nm. Sufficiently thick films (>0.4∼0.5 µm) deposited by the reactive sputtering show a columnar structure with an orientation of microcrystals {110} parallel to the substrate. As the orientation of the microcrystals develops with thickness, IR absorption bands due to Si–H stretching become sharper.

Effects of SiH[sub 2]Cl[sub 2] on the Deposition and Properties of Amorphous and Microcrystalline Silicon Fabricated from Very High Frequency Glow Discharges

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Nitrogen-Doping Effects on Electrical Properties of Hydrogenated Microcrystalline Silicon as Studied by Electron Paramagnetic Resonance and Conductivity

“…This may be interpreted as the interruption of the thermal excitation of electrons to the conduction band at low temperatures. In doped µc-Si:H, the EPR signal intensity of the conduction electrons exhibited a maximum at approximately 20 K. The temperature dependence suggests that the doped samples have shallower donor levels in µc-Si:H. This is supported by the fact that the EPR signals of the conduction electron are stronger in the N-doped samples (2)(3)(4) than in the undoped sample (1). We measured the conductivity of undoped and nitrogendoped µc-Si:H in the range of temperatures from room temperature to 77 K (Fig.…”

“…1,2) The µc-Si:H film has different electrical properties from hydrogenated amorphous silicon (a-Si:H), although both are prepared by a plasma-enhanced chemical vapor deposition (PECVD) method. [3][4][5] One of the most important properties with respect to application in actual devices is the considerable effect of impurity doping on the conductivity of µc-Si:H compared with a-Si:H. The phosphorous-doped and boron-doped µc-Si:H films exhibit the conductivity of 10 −1 -10 0 −1 cm −1 , which is higher than those of a-Si:H containing the same impurities. 6,7) In addition, conduction electrons have been observed by electron paramagnetic resonance (EPR) measurements in phosphorous-doped µc-Si:H, although they have not been observed in doped a-Si:H. 8) In the previous study, the nitrogen doping effect on the conductivity of µc-Si:H at room temperature was briefly reported.…”

“…depicts the Raman spectra of the undoped film (1) and nitrogen doped films(2)(3)(4)(5). The crystalline sizes estimated from Scherrer's formula using (111) XRaman spectra of undoped and nitrogen-doped µc-Si:H. The sample numbers are the same as inFig.…”

Effect of hydrogen dilution on the optical properties of hydrogenated amorphous silicon prepared by plasma deposition

“…This di erence between a-Si : H and a-Si is due to the existence of hydrogen in a-Si : H ® lms, that is hydrogen in these ® lms plays an important role in passivatin g silicon danglin g bonds (DBs) and thus in producing materials with suitable photoelectronic properties. Moreover, various types of structure, that is amorphous , microcrystalline and polycrystallin e forms, are attained in a conventional glow-dischar ge system using H 2 -diluted SiH 4 gas (Usui and Kikuchi 1979, Spear et al 1981, Mishima et al 1982, Kumeda et al 1982, Matsuda 1983, Imura et al 1984, Tsai 1989. A n interesting question is how the addition of H 2 to SiH 4 a ects the structure and the bonding scheme of the incorporated hydrogen in a-Si : H. We have already reported our preliminary results concerning the hydrogen dilution e ect (Y amaguch i and Morigaki 1991).…”