Thickness of the grown layers are measured and controlled within the range of tens of angstroms to several microns. Different layers must be doped, the donors or acceptors, to create pn-junction with a large concentration of electrons in the n-type region and holes – in the p-type region. In one process, which lasts several hours, the structure can be grown on 6 – 12 substrates of 50 – 75 mm. It is very important to ensure and monitor homogeneity of the structures on the surface of the substrate. The cost of facilities for epitaxial growth of semiconductor nitride, developed in Europe (the company Aixtron and Thomas Swan) and the U.S. (Emcore), about 1,5 – 2 million dollars. Experience of different companies showed that learn to get to this setup, the competitive structure with the necessary parameters can be a time of one to three years. This is – technology that requires high culture. An important step in technology is the planar Processing of films: their etching, creating contacts to n-and p-layers, the coating metal films for the pins. Film grown on a substrate can be cut by a few thousand chips ranging in size from 0,24 x0, 24 and 1×1 mm2. The next step is the creation of these led chips. Necessary to mount the crystal in the case, make contact conclusions, make optical coating, antireflective surface for the extraction of radiation or reflecting it. If it is a white light-emitting diodes, it is necessary to evenly phosphor. We must ensure that heat from the crystal and the corps, to make a plastic dome, focusing the radiation in the desired solid angle.
Month: September 2012
Microcomputers
In the same way described above in the case of declaration of GOING, translating a text and to interpret a word of missed form, it can all change the direction of the phrase, paragraph or even though change all the agreement on the same. Maintenance of Microcomputers Recently I read a possible article that spoke that 90% of the technician of computer science mount computers in wrong way and are of the international standards, and this factor is responsible for 67% percent of the problems presented in the existing computers in the whole world. I see many people if offering to make these types of works, either of small repairs, complete assembly, amongst others, and I know that many of these people are not formed, therefore, I myself I know some people who make and have friends that they are offered to make these types of works. Unhappyly had the question of the workmanship hand not to be so accessible, this type of ' ' presumptions profissionais' ' they gain space. Simple activities and that they can in general change life of Artesanato people If you like artisan manual works it type, are a good starting point there, much micron and small companies or liberal professionals, repass services of this type, a great example are the manual manufacture of leather belts and corino, that are tressed the hand, this activity can be income-producing to become in the vacant hours and the comfort of its home, mainly for owners of house or professionals of the home that cannot work outside because of the children who are small inside other factors. It has companies that they pay of R$ 1,50 until R$ 3,00 for each belt made for you. He locates somebody that makes and tries to learn, giving certain I I wait, you will go to remove the service and will execute in its house.