These include silicon, carbon, nitrites, carbides, oxides and also many others. In semi-conductor world, CVT is majorly used in the fabrication process of the semiconductor devices and to the exposure of the amorphous SiO2, Silicon Germanium and tungsten etc. The CVD is also the cause of the production of synthetic diamonds. The major importance of CVD in the industry lies in the fact that this process uses the gases as reactants. So the gas’s properties give much support to the reaction procedures. CVD is far most the best and reliable deposition phenomenon/process present. Its advantages include Versatile in nature – any element can be deposited either metallic or non-metallic About 99.99-99.999% pure results Formation of the material less than the melting point Nearly 100% density Economical There exist various types of Chemical Vapor Deposition. These include Atmospheric pressure CVD (APCVD), Aerosol Assisted CVD (AACVD), Hot Wire (HWCVD), Atomic Layer CVD (ALCVD), Low Pressure CVD (LPCVD), Metal Organic CVD (MOCVD), Plasma Enhanced CVD (PECVD) Rapid Thermal CVD (RTCVD), Remote Plasma Enhanced CVD (RPECVD), Microwave Plasma Assisted CVD (MPACVD) and Ultra High Vacuum CVD (UHVCVD). Introduction to High Density Plasma CVD Now I will start a proper introduction of the High Density Plasma Chemical vapor deposition HDP-CVD). The HDP-CVD process is majorly used for the dielectric gap filling in semiconductor devices manufacturing at very micro level. It is used for the Shallow Trench Isolation (STI) and the dielectrics inter layers in 180-nm, 130-nm and 90-nm technologies. Hope fully it will start for the 65-nm and 45-nm technologies too. Gap fillings at such a small scale are very difficult task. While doing the edge gap filling some factors are also keep in consideration like raising the wafer temperature, plasma density and lowering of the deposition pressure. The reaction chamber is used for the process. Scientists have developed the new generation tools for the higher plasma density. The HDP reaction chamber is included the two sources of the radio frequency (RF). These are coupled with the plasma as inductively and capacitively. Inductive RF controls the plasma density and capacitive RF controls the physical bombardment of ions to the wafers or substrates. The reaction chamber will be discussed in detail later on. HDP-CVD gives improved characteristics for the gap filling in the semiconductor fabrication. A process is explained here as an example. A semiconductor material or substrate is loaded in the reaction process chamber. The high density plasma is generated by the gases including oxygen, silicon, hydrogen and a chemical etching gas which is nitrogen free. This plasma is generated exactly on the substrate semiconductor. After this process the chemical semiconductor substrate is heated to a very high temperature. Normally it ranges from the 550 degree Celsius to 700 degree Celsius. This procedure helps in filling the gap regions without any side effects to the substrate. The layer for filling the gaps is of the silicon oxide. Fabrication Process The process of the high density plasma CVD comprised of the different claims which are as follows The steps which involved in the high density
HIGH DENSITY PLASMA CVD I start this article with the introduction to the Chemical vapor deposition (CVD). CVD is a chemical phenomenon of a material to deposit it on another material. This is done using thin films of the different materials. A typical CVD phenomenon includes the exposure of a material commonly in volatile format with the substrate which allows the reaction of those and obtains the desired result, deposit or exposure…
High blood pressure is a trait as opposed to a specific disease and represents a quantitative rather than a qualitative deviation from the norm. Taking into deliberation the importance of Blood pressure, National Health and Nutrition Examination Survey, (NHANES, 2009) considered blood pressure measurement as a major health concern.
Mostly, CVD is caused by the accumulation of extra plaque on the outer layer of a large blood—this is also referred to as ‘atherosclerosis’. This excess plaque disrupts the flow of blood to the brain or to the heart which causes heart attacks (Eaker et al., 1993).
ICI had employed the process of autoclave when they first commercialized the process in 1938. The tubular process was first invented by BASF in 1938 though it took another 15 years to commercialize the production processes. Cost reduction and product enhancement has been the goal of each manufacturer over the years.
There is a lot of competition as the resources are always in limited quantity in areas with dense populations. An area with dense but homogenous population has quite a better situation. The people all belong to the same kind and therefore, they learn to maintain status quo among them.
This mostly applies to humans. This increase in population density has got undesirable effects both on the environment and individuals. This is so because most of these populations dwell in comparatively small urban areas (Connelly, 2008). This increase in population density has got a direct correlation to increase in noise.
In a review of nine, nationally representative, large-scale studies in the US, it was found that compared with those that do not drink alcohol, relative risks were 0.95 (95% confidence interval [CI]: 0.88 to 1.02) among lifetime infrequent drinkers, 1.02 (95% CI: 0.94 to 1.11) among former drinkers, 0.69 (95% CI: 0.59 to 0.82) among light drinkers, 0.62 (95% CI: 0.50 to 0.77) among moderate drinkers, and 0.95 (95% CI: 0.82 to 1.10) among heavy drinkers (Mukamal, et al., 2010).
The most common type of heart problem is the narrowing of the coronary blood vessels. This disease is known as Coronary Heart diseases and is the main cause of heart attacks. Coronary Heart disease (Coronary artery disease) is better known as Coronary atherosclerotic heart disease or simply atherosclerosis, in which the arteries become narrower and disrupt the blood flow.
It is also predicted that the heart ailments and stroke would be the major causes of death and disability that would result in more than 24 million fatalities in an year by 2030 (WHO, 2004). The proportion of the deaths reported from United States due to Coronary vascular disease is also 30 and this is reported maximum for the age groups above 65 (United States, 2006)
It is also predicted that the heart ailments and stroke would be the major causes of death and disability that would result in more than 24 million fatalities in an year by 2030 (WHO, 2004). The proportion
The patients are subjected to drugs that lower the level of cholesterol in the blood so that patient can have safe life. Hypercholesterolemia can not be left untreated as other major diseases arising due to it can
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