The word is derived from the Greek epi meaning above, and taxis meaning in an ordered manner. In the forming of layers, it involves the deposition of silicon or silicon compounds that help to continue and perfect the crystal structure of the bare silicon wafer below. The electrical characteristics of the Epi wafer surface are improved by epitaxy, which makes it suitable for highly complex microprocessors and memory devices. Selective Epitaxy is an Epitaxy process that on certain predetermined areas of the wafer only deposits silicon or a silicon compound.
Events Occurring During Epitaxy
To form the transistor channel region, as well as the source and drain, there is the selective deposition of Epitaxial layers. The source is the point where charge carriers like electrons enter the channel, and they leave from the drain. There is a gate between them that controls the conductivity of the channel. It can be even switched to allow electrons to flow or to prevent them from flowing. Epi wafer manufacturers can dope Epitaxy films to very precise concentrations of the dopant elements by combining them with additional elements in the processing source gases.
Advantages
In a highly controlled manner Epitaxy improves the electrical characteristics of the wafer surface, making it very much suitable for highly complex microprocessors and memory devices.
In the current scenario, we see that in the microelectronics industry CMOS technology is the driving technology, and the conventional way of fabricating integrated circuits on bulk silicon substrates has given problems such as the difficulty of making shallow junctions, unwanted parasitic effects, and latch-up. In recent years, in many aspects to their bulk counterparts, the advent of Silicon-on-Insulator has proven superior. The advantages here are the absence of latch-up, ability to operate at high temperature, the ease of making shallow junctions, radiation hardness, the reduced parasitic source and drain capacitances, improved transconductance, and sharper sub-threshold slope.
In creating SOI wafers there are several approaches available and here we discuss two particular techniques. First, through the Ultra-Thin Silicon process where high-quality Silicon-on-Sapphire (SOS) material is formed we seek to illustrate a heteroepitaxy technique. Next, to grow a homogenous crystal laterally on an insulator Epi wafer supplier look at a homoepitaxy technique called Epitaxial Lateral Overgrowth (ELO) technique which seeks.
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