Toshiki Kaneko

Change in crystalline morphologies of polycrystalline silicon films prepared by radio‐frequency plasma‐enhanced chemical vapor deposition using SiF4+H2 gas mixture at 350 °C

Polycrystalline silicon films have been deposited on glass substrates at 350 °C by radio‐frequency plasma‐enhanced chemical vapor deposition using a SiF4+H2 gas mixture. Crystalline fraction decreased abruptly with increasing gas flow ratio. Film structure drastically changed by increasing gas pressure from 0.4 to 2.0 Torr. At lower gas pressure, columnar crystals 30 nm in diameter grew from the glass substrates, while at higher gas pressure larger columnar crystals with a maximum diameter of approximately 100 nm grew on an amorphous Si layer approximately 170 nm thick.

Crystalline Fraction of Microcrystalline Silicon Films Prepared by Plasma-Enhanced Chemical Vapor Deposition Using Pulsed Silane Flow

Microcrystalline silicon (?c-Si) films have been prepared at 200?C by radio-frequency (rf: 13.56 MHz) plasma-enhanced chemical vapor deposition using pulsed silane flow. The crystalline fraction, Xc(Raman), of ?c-Si films approximately 200 nm thick is quantitatively determined by decomposing Raman spectra into three peaks: crystalline, intermediate (small-grain-size-crystalline), and amorphous. The effects of rf power on Xc(Raman) and hydrogen content, CH, have been studied. Xc(Raman) increases with increasing rf power and tends to saturate; the maximum value of Xc(Raman) is 71%. With increasing rf power CH decreases to a minimum value of 4.5% and then increases. Hydrogen introduction into Si films overlapped with hydrogen elimination is responsible for the increase and saturation of Xc(Raman) with rf power.

400 dpi integrated contact type linear image sensors with poly-Si TFT's analog readout circuits and dynamic shift registers

Four-hundred-dots-per-inch (dpi) sensors, including poly-Si thin-film-transistor (TFT) scanning circuits, and a-Si photodiodes fabricated on borosilicate glass have been developed. This contact-type image sensor contains TFT analog buffer amplifiers in the readout circuits. The scanning circuits can operate in a frequency range between 200 kHz and 1 MHz. The readout circuits incorporating TFT analog impedance converters decrease photodiode impedance by more than three orders of magnitude and improve the linearity between illumination intensity and the sensor output. High-resolution reading is achieved by the new contact-type linear image sensors with a storage time of 2 ms/line. >

Crystallinity Analysis of Amorphous-Crystalline Mixed Phase Silicon Films Using EXAFS Method

The crystalline phase fraction (Xc) of amorphous-crystalline mixed phase Si films prepared by thermal annealing of a-Si:H films and by plasma CVD and chemical annealing methods was investigated by an EXAFS method. The EXAFS spectra of these films were represented by linear-combination of a-Si:H and c-Si EXAFS spectra. The values of Xc were analyzed by least-square curve fitting. Furthermore, the Xc values analyzed by a conventional Raman method were calibrated by the EXAFS analysis results.