Polycrystalline silicon

About: Polycrystalline silicon is a research topic. Over the lifetime, 19554 publications have been published within this topic receiving 198222 citations. The topic is also known as: polysilicon & poly-Si.

Correlation between Microstructure and Photovoltaic Performance of Polycrystalline Silicon Thin Film Solar Cells

Abstract: Intrinsic polycrystalline silicon (poly-Si) thin films have been prepared by plasma enhanced chemical vapor deposition at a very high excitation frequency (100 MHz) for the development of p–i–n junction solar cells. The correlation between poly-Si microstructure and photovoltaic performance of poly-Si solar cells has been investigated as a function of deposition parameters such as deposition pressure, SiH4 flow rate and SiH4 concentration. It is found that the poly-Si microstructure including crystalline volume fraction, Xc, and crystallographic orientation is closely related to the atomic hydrogen flux during film growth, which is evidenced by plasma diagnostics in the in situ measurement of optical emission spectroscopy. Basically, with an increase in Xc, open circuit voltage tends to decrease, while poly-Si with Xc > 50% and (220) preferential orientation is essential for high short circuit current. Based on these results, the role of poly-Si microstructure in the photovoltaic performance of poly-Si solar cells is discussed.

Semiconductor device wiring or electrode

Abstract: A MOSFET in which the gate electrode is formed of a polycrystalline silicon film, a silicon nitride film having a nitrogen surface density of lens than 8×10 14 cm -2 , and a tungsten film--these films formed one upon another in the order mentioned. The gate electrode thus formed, serves to shorten the delay time of the MOSFET.

Solid state image sensor

Abstract: A solid state image sensor including a plurality of sensing cells, each formed of a switching transistor and a thin film sensing device, arranged in a line or a matrix. The switching transistor is a thin film transistor (TFT) of polycrystalline silicon and the thin film sensing device utilizes a layer of amorphous silicon formed on a lower electrode which is electrically connected to the drain of the switching.

Vacuum sealing of microcavities using metal evaporation

Abstract: A new encapsulation technique to seal a vacuum-tube microcavity hermetically at low pressures, based on aluminium evaporation, is presented and its performance is compared to conventional low-pressure chemical vapour deposition (LPCVD) reactive sealing. The microdiode consists of an in-cavity recessed single-crystalline silicon cathode tip above which a polycrystalline silicon anode is suspended on a silicon-rich nitride layer. The diode cavity is cleared from the sacrificial oxide in buffered HF through the horizontal etch-access channels between the polysilicon anode and the silicon-rich nitride isolation layer. Vacuum sealing of the cavity using LPCVD polycrystalline silicon results in polysilicon deposits ( > 50 nm) inside the cavity, and thus in a non-acceptable degradation of the cathode-tip curvature. When sealing is performed using aluminium evaporation, no deposits inside the cavity are observed and pressures below 10 Pa can be expected. Applications of the technique presented are not restricted to micro vacuum diodes, but also include various type of hermetically sealed micromechanical structures, where deposits inside the sealed cavity are undesirable.

Characterization of low-temperature processed single-crystalline silicon thin-film transistor on glass

Abstract: Single-crystalline silicon thin film on glass (cSOG) has been prepared using an "ion-cutting" based "layer-transfer" technique. Low-temperature processed thin-film transistors, fabricated both on cSOG and metal-induced laterally crystallized polycrystalline silicon, have been characterized and compared. The cSOG-based transistors performed comparatively better, exhibiting a significantly higher electron field-effect mobility (/spl sim/430 cm/sup 2//Vs), a steeper subthreshold slope and a lower leakage current that was also relatively insensitive to gate bias.