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becoz it is very cheaper than germanium and also it is mainly used inducing negative ions (electrons ).
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Why poly-silicon is used as gate material instead of metal?
we use polysislicon instead of metal because polysilicon has the self aligned property.
What a difference between dry and wet oxidation?
Dry oxidation has a lower growth rate than wet oxidation although the oxide film quality is better than the wet oxide film. Therefore thin oxides such as screen oxide, pad oxide, and especially gate oxide normally use the dry oxidation process. Dry oxidation also results in a higher density oxide than that achieved by wet oxide and so it has a higher breakdown voltageIn case of wet oxidation where water is use instead of oxygen, the water molecule can dissociate at high temperatures to form hydroxide OH that can diffuse in the silicon faster than molecular O2. Therefore the wet oxidation process has a significantly higher oxidation rate than the dry oxidation. It is used to grow thick oxides such as masking oxide, blanket field oxide, and the LOCOS oxide.
How is silicon sulfide used?
Silicon Sulfide is a compound of silicon. It is used to make glass such a windows and eye glasses and also to make microchips and containers.
What is the principal mineral used in making glass?
Glass is manufactured primarily from the mineral quartz (SiO2) which is what sand is made from. However small amounts of other minerals are added to the sand to make the process easier. These minerals are:- sodium carbonate (Na2CO3) lime (calcium oxide (CaO) magnesium oxide (MgO) aluminum oxide (Al2O3) There are also other minerals which are added to make specialised glasses. e.g. Pyrex glass is made from sand and boron oxide.
What is carbon tetra fluoride used for?
from wikipedia: "Tetrafluoromethane is sometimes used as a low temperature refrigerant. It is used in electronics microfabrication alone or in combination with oxygen as a plasma etchant for silicon, silicon dioxide, and silicon nitride.[4]"
Why silicon dioxide used in MOSFET instead of any other material which have high k-dielectric?
Because the gate terminal should highly resistive..silicon dioxide has high resistance and hence gate current is very very low...
What are the differences betweeen e-mosfet and d-mosfet?
An e-mosfet is and "enhancement" mosfet. A d-mosfet is a "depletion" mosfet. These essentially show what mode the mosfet operates in when a voltage is applied to the gate. . An enhancement mode mosfet is normally non-conducting but conducts when the channel is enhanced by applying a voltage to the gate and pulling carriers into the channel. A depletion mode mosfet normally conducts but becomes more and more non-conducting as carriers are depleted or pulled out of the channel by applying a voltage. The polarity of the voltage depends on whether it is an N channel or P channel. P channel uses positively doped silicon while N channel uses negatively doped silicon. N channel fets are used wherever possible because N material conducts better than P material. There are basically two types of fet, the jfet and the mosfet. The jfet uses a single junction to control the channel hence draws some current. Bipolar transistors use two junctions. In the mosfet (Metal Oxide Semiconducting Field Effect Transistor) there is no such junction hence draw so little current for control purposes it can be regarded as zero. The gate is isolated from the channel by a very thin layer of metal oxide (usually chromium dioxide). An enhacement mode mosfet can be turned on by applying a voltage then removing the wire to the gate. The channel will then remain conducting for some time.
What element is used in the making of glass?
Silicon ... or more correctly silicon oxide.
What are the differences in the properties between the silicon substrate and the oxide layer?
Silicon Substrate Silicon substrates are mainly used for power semiconductors in automotive, electronics and HF front-end pa. silicon that can be fused with other materials, such as thermal oxide and or silicon nitrite. Oxide Layer An oxide layer is a thin layer or coating of an oxide, such as iron oxide. Such a coating may be protective, decorative or functional. It is a passivizing layer on the surface of the metal, preventing further corrosion.
Why is aluminum oxide used more frequently than silicon carbide as an abrasive?
price
What element is used in borosilicates?
There are a couple derivatives of elements that are used in borosilicate glass. They are boron oxide and silicon dioxide.
Can you replace mosfet with an bjt transistor?
A MOSFET (metal oxide semiconductor field effect transistor) can be used INSTEAD of a BJT (bypolar junction transistor, so transistor is redundant in your question), if the circuit in question is modified to allow it and the MOSFET is chosen appropriately. BJT's will usually have a higher intrinsic gain, but have lower input resistance. Also a BJT in general will work better at higher frequencies than a MOSFET (unless you choose a high frequency MOSFET) due to the capacitive nature of MOSFETs.
Why self bias is not used in enhansement type MOSFET?
Because for creating channal we need voltage at gate if there is no voltage at ate then VGS=0 this mean no amplificatiion can be done.
Can depletion mosfet act as enhancement mosfet?
It depends. A depletion MOSFET can be used as an ehancemnet MOSFET when it is operated as an analog amplifier. However, a depletion MOSFET can't replace an enhancement MOSFET when it is operated as a digital switch. When a depletion MOSFET is used as a digital switch, since the junction between source terminal and substrate must be reverse biased, the voltage of the source terminal of an N typde transistor must be tied to Vdd, and it is completely opposite to an enhancement MOSFET. When a depletion MOSFET is used as an analog amplifer, the source terminal and the substrate are both at the same potential, just like an enhancement MOSFET.
What is the difference between jfet and mosfet?
1-BJT is bipolar while JFET is unipolar. 2-BJT has low input impedence while JFET has high input impedence. 3-JFET has low power discipation as compared to BJT. 4-JFET has low noise as compared to BJT. 5-BJT is current controlled while JFET is voltage controlled. 6-JFET is mostly used in digital circuits.
What transistor is used in VLSI?
MOSFET
What is polycrystalline silicon used for?
Simulant DiamondsIn solar cells... http://en.wikipedia.org/wiki/Polycrystalline_silicon_photovoltaicsAlso Gate material in MOSFETS...
