Low pressure chemical vapor deposition LPCVD

In this sub-subsection, the Er doping of amorphous silicon is discussed. The problem of limited solubility of Er in crystalline silicon has been circumvented. However, the electrical properties of pure a-Si are poor compared to c-Si. Therefore, hydrogenated amorphous silicon is much more interesting. Besides, the possibility of depositing a-Si H directly on substrates, i.e., optical materials, would make integration possible. Both low-pressure chemical vapor deposition (LPCVD) [664] and PECVD [665, 666] have been used to make the a-Si H into which Er is implanted. In both methods oxygen is intentionally added to the material, to enhance the luminescence. 

Low polarity plasticizers, 74 479 Low power package, 74 863 Low pressure catalytic processes, 20 151 Low pressure chemical vapor deposition (LPCVD), 5 807, 811-812 Low-pressure gas separation, spiral-wound membrane modules for, 75 823-824 Low pressure hollow-fiber membranes, 76 24-26... 

A schematic view of the cold cathode fabrication process is shown in Fig. 10.18. The cold cathode is fabricated by low pressure chemical vapor deposition (LPCVD) of 1.5 pm of non-doped polysilicon on a silicon wafer or a metallized glass substrate. The topmost micrometer of polysilicon is then anodized (10 mA cnT2, 30 s) in ethanoic HF under illumination. This results in a porous layer with inclusions of larger silicon crystallites, due to faster pore formation along grain boundaries. After anodization the porous layer is oxidized (700 °C, 60 min) and a semi-transparent (10 nm) gold film is deposited as a top electrode. 

The wafers were coated with silicon dioxide (400 nm thickness) and silicon nitride by low pressure chemical vapor deposition (LPCVD) alternately. The chips were fabricated by photolithography and etching. The catalyst (for the application Pt) was introduced as a wire (150 pm thickness), which was heated resistively for igniting the reaction. The ignition of the reaction occurred at 100 °C and complete conversion was achieved at a stochiometric ratio of the reacting species generating a thermal power of 72 W (Figure 2.28). 

A promising alternative is surface textured doped zinc oxide films. ZnO films can offer excellent transparency and are highly resistant to hydrogen plasmas [78]. Textured ZnO films have been prepared by several deposition techniques. Examples are boron doped zinc oxide (ZnO B) prepared by low-pressure chemical vapor deposition (LPCVD) ([79,80], see also Chap. 6) or ZnO films deposited by expanding thermal plasma CVD [81], Quite recently, ZnO films for back contacts of solar modules have been developed using chemical bath deposition [82]. 

A totally different approach to produce zinc oxide as transparent contacts with a rough surface utilizes low pressure chemical vapor deposition (LPCVD). Excellent results have been achieved with this type of substrate [158], which are described in detail in Sect. 6.3.2.2 of this book. 

Sacrificial oxide. The sacrificial oxide layer is deposited by low-pressure chemical vapor deposition (LPCVD) or plasma-enhanced chemical vapor deposition (PECVD). The layer is made of either undoped glass or phosphorous-silicon glass (PSG)-doped resulting in a final thickness of 1.5-2.5 pm. Low defect density, good etch rate control, uniformity and stress control have been accomplished for updoped oxide with a Novellus Concept One tool. 

Numerical thermo-mechanical studies have been performed to improve the robustness of the membrane, addressing buckling and stress concentration (Puigcorb6 et al., 2003). Thermo-mechanical reliability depends on the design and materials used. In general, the membranes made of dielectric materials deposited at a higher temperature (e.g. low-pressure chemical vapor deposition - LPCVD) are more robust. The membrane is usually formed of a stress-compensated stack of thin films of silicon nitride, silicon oxynitride and/or silicon oxide. A heater embedded in between LPCVD low-stress silicon nitride thin films has proven to be robust (Demarne et al.,... 

Silica-based PLCs are fabricated with various kinds of technologies. The substrate material is either silica or silicon. Several typical fabrication technologies are (1) flame hydrolysis deposition (FHD), (2) low-pressure chemical vapor deposition (LPCVD), and (3) plasma-enhanced chemical vapor deposition (PECVD). FHD will be de-... 

In this process, as shown step-by-step in cross section in Figure 1.7, the surface of a 150 mm substrate (n-type, 1-2 Qcm) is heavily doped with phosphorus to a resistance of 10 Q/D to avoid charge buildup at the substrate-nitride interface when high voltages are applied between the substrate and the subsequent conducting layers. The surface is protected by a blanket low-pressure chemical vapor deposition (LPCVD) of a 0.6 pm thick insulating silicon nitride (90 MPa residual tensile stress). A 0.5 pm thick layer of LPCVD polysilicon (n-type, 30Q/D, 25 MPa residual compressive stress) PolyO is... 

Low pressure chemical vapor deposition (LPCVD) Here, deposition takes place at low pressure (1 Torr). This process is primarily used for polysilicon, which is a fundamental material for MEMS. The deposition speed for this process is about Ipm/h. 

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