Silicon dioxide applications

An RF plasma is generated at a frequency of 13.56 MHz. A typical equipment consists ofparallel electrodes as shown inFig. 5.20. It is a cold-wall design which is used extensively forthe deposition of silicon nitride and silicon dioxide for semiconductor applications. 

Silicon dioxide (Si02), also known as silica, is a major industrial material with many applications particularly in the semiconductor industry in the form of coatings, which are produced mostly by CVD. It is an excellent electrical insulator with very low thermal expansion and good resistance to thermal shock. Its characteristics and properties are summarized in Table 11.4. 

Many reactions are being used to deposit silicon dioxide, both experimentally and in production, and many more are being investigated in the laboratory. The selection depends on the application, the temperature limitations, the type of equipment available, and other factors. 

Chuyiko AA (2003) Medical chemistry and clinic application of silicon dioxide. Russian Naukova Dumka, Kiev. 

Next, let us consider the applicability of this unique wettability phenomenon. With Ti02 photocatalyst alone, this highly amphiphilic surface disappears soon after exposure of the surface to light. When the photocatalyst has been combined with a water-sorbing substance that can hold water within its structure (such as silicon dioxide or silica gel), the effect of the surface continues even in the dark. Fogging of the surfaces of mirrors and glass occurs when steam that has cooled on these surfaces form many water droplets. On a highly amphiphilic surface, no... 

Abstract—The adhesion of pyromellitic dianhydride-oxydianiline (PMDA-ODA) polyimide to fluorine-contaminated silicon dioxide (F-SiO,) with y-aminopropyllriethoxysilane (APS) adhesion promoter has been studied as a function of the peel ambient humidity. The peel strength was not affected by the change in peel ambient relative humidity (RH) from 11-17% to 35-60% when APS was used at the interface. Without APS, the adhesion degraded significantly with this change in RH. It was found that although the dip application of APS caused the removal of about 80% of the initial atomic percentage of fluorine on the surface, it could not be totally removed even after several days in water at elevated temperature. 

Adhesion of polyimides to inorganic substrates is of great importance to the microelectronics industry [1, 2]. The polyimide films are deposited most often by spin coating the polyamic acid (PAA) usually from a TV-methylpyrrolidone (NMP) solution onto the substrate surface followed by thermal imidization at temperatures up to 400<>C. The most studied polyimide is the pyromellitic dianhydride-oxydianiline (PMDA-ODA), which exhibits excellent mechanical and dielectric properties, but not so good adhesion characteristics. The latter has been generally overcome by application of an adhesion promoter, such as y-aminopropyltriethoxysilane [3-7]. The reactions of APS (coated from water solution) with the silicon dioxide surface as well as with polyamic acid have been well characterized by Linde and Gleason [4] however, we do not have such detailed information available on APS interaction with other ceramic surfaces. 

In conclusion, the sodium sulfate mixed with rare earth sulfates (Ln=Y and Gd) and silicon dioxide exhibits high electrical conductivity and is more durable than the pure sodium sulfate. Furthermore, the Na-SO, -Y (S0, -SiO solid electrolyte ipaintains a similar phase to Na-oO -I, whicn is excellent in Na+ cation conduction. The measured EMf was in excellent accordance with the calculated EMF, at SO2 gas concentration in the range of 30 ppm to 1 %. In fact, the solid reference electrode method could be applicable as a practical SO2 gas detector. 

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). 

It has been suggested [95] that the synthesis of structured porphyrins with controllable steric ambience is a strategic direction in the reproduction of enzyme protein cavities, which control the selectivity and stability of biochemical reactions such as cytochrome P-450. Such an approach to the synthesis of biomimics has considerable potential, especially in their application on mineral matrices silicon dioxide, alumina and zeolites. Data exist on the synthesis of a biomimic [96] with a complex porphyrin complex (5-pentafluorophenyl-10,15,20-tri(2,6-dichlorophenyl)porphyrin (FeMPFDCPP)) covalently linked to aminopropyl silicon dioxide, which is applied in oxidation of ds-cyclooctene, cyclohexene, cyclohexane and adamantane with participation of iodosylbenzene dissolved in dichloromethane. 

Silicon dioxide films have been an essential factor in the manufacture of integrated circuits from the earliest days of the industry. They have been used as a final passivation film to protect against scratches and to getter mobile ion impurities (when doped with phosphorus). Another application has been as an interlayer dielectric between the gate polysilicon and the aluminum metal-ization. Initially, most such films were deposited in atmospheric pressure systems. In recent years, low pressure processes have assumed greater importance. We will begin by examining the atmospheric process. 

There are two aspects of tungsten CVD for integrated circuits that have taken on commercial importance. One is the blanket deposition and subsequent patterning, so it can be used as a conductor to replace high-resistivity doped poly. The second area of interest is the "selective" CVD of tungsten, where deposition occurs on silicon but not on silicon dioxide. Here one can selectively fill via holes to either provide a thin barrier metal or to deposit a thicker layer to help planarize the circuit. Both applications involve only one processing step, and are attractive for this reason. 

In the present chapter, we will review the nature of plasma-enhanced CVD (PECVD) films for a variety of applications. We will look at dielectrics (silicon nitride, silicon dioxide), semiconductors (polysilicon, epi silicon) and metals (refractory metals, refractory metal silicides, aluminum). There are many other important films (i.e., amorphous silicon for solar cells and TiN for tool harden-... 

In order to improve the separating performance of HPTLC pre-coated plates silica gel 60 even at larger applied volumes, as may be necessary at low sample concentrations, and with a rapid and simple technique of application, HPTLC pre-coated plates silica gel 60 with so-called "concentrating zones" were developed (10, 11, 12). This type of plate consists of two distinct layer sections, namely the separating layer proper consisting of silica gel 60 and a concentrating zone composed of an inert, porous silicon dioxide. These two sorbent materials pass into one another at a clearly defined boundary-line in such a way that the eluant is offered no resistance as it passes through. 

Medicinal Chemistry and Clinical Application of Silicon Dioxide, edited by A. A. Chuiko (Naukova Dumka Kyiv, 2003). 

Medical chemistry and the clinical application of silicon dioxide, edited by Chuiko A. A. (Naukova dumka, Kiev, 2003). 

It is expected that the sensitivity of positrons and positronium to changes in the matrix material will be used extensively in the near future. For example, tantalum-silicon-nitride was found to be an effective diffusion barrier between copper and silicon dioxide [34]. The applicability to porous materials needs to be checked. Work has been carried out, for example, by Gidley et al. on TiN diffusion barriers [35],... 

---