Why it is difficult for silicon to operate at high temperature?
Silicon is a semi conductor in normal temperature. At high temperature it becomes conductor rather than a semiconductor.
Silicon devices are easily passivated and so can be packaged in inexpensive molded plastic packages, while germanium devices must be packaged in more expensive hermetically sealed glass, ceramic, or metal packages. Silicon devices can operate up to 150C junction temperature, making them more suitable for high power use than germanium devices, which can only operate up to 60C junction temperature, Silicon is a less expensive, more plentiful material than germanium. (Germanium was used more initially…
Silicon is actually preferred to germanium within the manufacture of semiconductor devices due to the following reasons: Silicon is cheap and abundant In silicon, leakage current is less affected by temperature as compared to germanium. The leakage current in silicon is very very small as compared to germanium. The working temperature of silicon is more than that of germanium. The working junction temperature of silicon can go as high as 150C whereas the working junction…
What is the state of matter of an ionic compound and what is the state of matter of covalent compound?
It depends on the temperature. Ignoring the effects of pressure the following are true:- At room temperature ionic compounds are solids. At high temperature they melt. Molecular covalent compounds may be gaseous , liquid or solid ate romm temperature. Giant covalent molecules such as silicon dioxide are solids at room temperature and melt at high temperature.
A student asserts that silicon and germanium become good insulators at very low temperatures and good conductors at very high temperatures. Do you agree?
silicon and germanium have 4 valence electrons...they will be bound by covalent bonds at very low temperature..hence there will be no delocalized electrons to conduct electricity..therefore at low temperature these two elements behave like insulators....at high temperature,the energy will be sufficient to break the covalent bond and thus electrons become delocalized....therefore at high temp they behave like conductors
Glass is Silicon Dioxide (SiO2) Silicon is unreactive chemically because an oxide layer seals the surface from attack, and high temperatures are required for oxidation to occur. Silicon does, however, react with fluorine at room temperature. It is not attacked by aqueous acids, but does react with concentrated alkalis. Source: google
Why silicon dioxide is a solid with a high melting point while carbon dioxide is a gas at room temperature?
Carbon can form double bonds to oxygen allowing carbon to achieve an octet, silicon cannot, there is next to no evidence for a Si=O. It is all due to poor overlap between 3p orbital on Si and the 2p orbital on O. Silicon goes down the polymerisation route, silicon atoms surrounded tetrahedrally by oxygen atoms that bridge between silicon atoms. Interestingly high pressure results (2007) for carbon dioxide show that at high (> 1GPa, 10,000…
Electronic elements are mainly composed of semiconductor elements which are carbon , silicon and germanium of which carbon acts as conductor due its layer like internal structure n germanium is very rarely available but where as silicon is most abandantly available n have high temperature coefficient n cheaper in cost.
Answer Silicon is abundant in nature as SiO2(sand). Getting the Si from SiO2 is comparatively easier than other semiconductors like Ge. And Silicon is a better conductor at room temperature. valence electron in germanium are in fourth shell whereas on silicon valence electron is in third shell. germanium valence electron are at higher energy level than silicon .hence germanium valence electron will need smaller amount of energy to escape form the atom due to this…
Generally SCR is used at high power applications, in order to withstand the temperature dissipated in the SCR, THERMAL STABILITY is very high enough. It means that thermal stability of silicon is very high compared to germanium that's why germanium is not preferred. But that does not mean it is not possible, in fact before silicon became common in the 1960s devices equivalent to the SCR were built using germanium!
Actually in the late 1950s and early 1960s when germanium was the dominate semiconductor, devices similar to the SCR were made with germanium. They were called thyristors, similar to the gas filled tube the thyratron. However as germanium can only operate up to junction temperatures of about 60C and silicon can operate up to junction temperatures of 150C, it is much easier to make high power SCRs than thyristors. Also germanium devices must be packaged…
It has a high strength to weight ratio, meaning that it is strong but still very light. It also is very resitant to corrosion, and can operate at relitively high temperatures. On the negative side, it can cost a lot as it is difficult and expensive to extract from ore. It is also difficult to work with - it can't be heated and formed in the same way as steel.
Silicon Valley is an area in Northern California known for high technology products and research. Venture capitalists took risks with their funds to hopefully produce high technology products that have been profitable and useful for the world. With high risk investing, the products of Silicon Valley may have never amounted to much.