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The electrical properties of silicon nanocrystals (Si NCs) embedded in silicon-rich silicon nitride (SRSN) films were investigated by fabricating metal-insulator-semiconductor capacitor structures to utilize the Si NCs as charge storage nodes. The Si NCs embedded in SRSN films were prepared by catalytic chemical vapor deposition technique at substrate temperatures below 200 °. The counterclockwise hysteresis loops were observed in capacitance-voltage (C-V) characteristics. A memory window of 13 V was observed in the sweep voltage range of ±12 V.

We studied the effect of in-situ hydrogen annealing on dielectric SiNx films at a low-temperature (150 oC) by Cat-CVD. The in-situ hydrogen annealing was performed without a vacuum breaking. After in-situ annealing, furnace annealing was performed for 2hours below 150 oC. The C-V, and I-V characteristics were measured by MIS structure. The high hydrogen ratio sample showed better dielectric properties improvement by annealing. SiNx films dielectric properties were extremely improved by in-situ hydrogen annealing and furnace annealing. Breakdown field was 6 MV/cm. C-V hysteresis window was reduced from 15 V to 1 V. The on/off ratio of TFT was 105. The Mobility was 0.23. We successfully fabricated dielectric SiNx films at the low temperature, and also a-Si TFTs at the same temperature by Cat-CVD.

The solid phase compositions and dielectric properties of silicon nitride (SiNx) films prepared using the plasma enhanced chemical vapor deposition (PECVD) technique at a low temperature (200°C) we...

Since the visible photoluminescence (PL) from porous silicon was reported [1], investigation of light-emission diodes (LEDs) using silicon (Si) quantum dots (QDs) has been investigated. Many researchers have studied luminescence from Si QDs embedded in silicon oxide or nitride films [2-4]. However, these materials have demerit that the high operation voltage was required because of using insulator. Silicon carbide film has lower resistivity than the silicon oxide or nitride film. The silicon carbide films have an advantage in manufacture of p-i-n LEDs because those were easily able to dope. In this work, we studied electrical properties of the silicon rich silicon carbide (SRSC) films deposited by catalytic chemical vapor deposition (Cat-CVD) technique. A mixture of SiH4, CH4 and H2 gas was employed as the source gas in deposition process. Atomic composition of SRSC films and formation of Si QDs in SRSC films depended on control of SiH4/CH3 mixture ratios. The each different tunneling behavior was observed in currentvoltage (I-V) curve of two samples prepared at different SiH4/CH3 mixture ratios. The PL spectra of two samples were also each different. These results were analyzed with relating formation of Si QDs in SRSC films. Figure 1 shows I-V characteristics of the SRSC films deposited at two different SiH4/CH3 mixture ratios. The SiH4/CH4 mixture ratios were 10 and 1 in figure 1(a) and figure 1(b), respectively. In figure 1(a), the experimental data were fitted well with the Fowler-Nordheim equation expressed as follows [5]: ( ) V b aV IFN / exp 2 − = (1)

The dielectric property has great influence on characteristics of bottom-gate nanocrystalline silicon thin film transistor at low process temperature ({less than or equal to} 200°). For improving the quality of the gate dielectric layer, in-situ hydrogen annealing step in the silicon nitride deposition process was attempted in low process temperature by catalytic CVD system. The in-situ hydrogen annealing was effective in advanced field effect mobility and capacitance-voltage characteristic by decreasing the defects inside the SiNx film.

Si/SiC composite films, namely, Si nanocrystals in a-SiC matrix material, were deposited by using Cat-CVD. Photoluminescence characteristics of a-SiC thin films prepared with various gas ratio R=[CH4]/[SiH4] were investigated. Fourier-transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS) measurements composition ratio of a-SiC films. It shows different composition ratio between R > 10 and R < 10. Photoluminescence (PL) intensity was changed before and after thermal annealing at various temperatures. The PL intensity was increased after annealing peak position was shift short wavelength range.

We observed a wide range of photoluminescence (PL) energy variation from silicon nanocrystals prepared at a low temperature (⩽200 °C). The size of the silicon nanocrystals was controlled by varying the NH3/SiH4 mixture ratio. The PL peaks consist of three compounds: nanocrystalline silicon, amorphous silicon and nitrogen dangling bond. The luminescence from the silicon nanocrystals was dominant, and its wavelength varied from 510 to 710 nm as the subgrain size changed from 3.5 to 5 nm.

Nanocrystalline silicon (nc-Si) thin films that are deposited at low-temperatures (

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— The effect of in-situ hydrogen pretreatment on dielectric properties of silicon nitride (SiNx) thin films for a gate dielectric layer has been studied. SiNxthin films were grown at a low temperature (150°C) by Catalytic CVD followed by conventional furnace annealing at 150°C for 2 hours. The in-situ hydrogen pretreatment was performed without vacuum break before the sample was transferred to the furnace for thermal annealing. Capacitance—voltage (C-V) and current-density—voltage (J-V) measurement showed that the hydrogen pretreatment was effective in reducing the hysteresis in the C-V curve and in increasing the breakdown voltage. Without the treatment, the 150°C annealing failed to produce reliable C-V and I-V characteristics. The C-V hysteresis and the threshold voltage shift of SiNx were improved by furnace annealing as the hydrogen dilution ratio increased. Also, addition of hydrogen to the deposition gas mixture helped to improve the dielectric properties of the SiNx films after thermal annealing. The combination of hydrogen dilution of the source gas and the in-situ hydrogen treatment was successful in producing low-temperature SiNx films applicable to a-Si TFTs. The TFT fabricated by using these films showed a field-effect mobility of 0.23 cm2/V-sec and a Vth of 3.1 V.

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The silicon nanocrystals embedded in silicon-rich silicon nitride films were deposited by catalytic CVD at low temperature (≤200 °C). Excimer laser annealing and in-Situ H2 treatment were performed to increase quantum efficiency. Electrical properties of metal-insulator-semiconductor structures using these samples were measured.

We studied excimer laser annealing effects on silicon-rich silicon nitride films containing silicon quantum dots to develop silicon based flexible Light emitting diodes. The silicon-rich silicon nitride films were deposited by catalytic chemical vapor deposition system using a mixture of SiH4, NH3 and H2 gas. The substrate temperatures in all deposition process were less than 200 ° to use polyethersulphone substrate. The changing crystallity and density of silicon quantum dots were analyzed by photoluminescence spectra. The change in the luminescence behavior with nucleation of silicon quantum dots was observed after excimer laser annealing.

The nanocrystalline silicon bottom-gate thin film transistor (nc-si TFT) should improve on formed amorphous incubation layers at the onset of deposition because these layers deteriorate the performance of the transistor. We attempted modulation of hydrogen dilution ratio to achieve both the minimal incubation layer and high deposition rate. The incubation layer thickness was estimated by transmission electron microscopy (TEM) and crystallization fraction was measured by Raman spectroscopy.