Brand Name: CazenOveyi
Model Number: LT1210CT7 LT1210 CT7 TO-220-7
Operating Temperature: International standard
Supply Voltage: International standard
Dissipation Power: International standard
Electronic Components & Supplies: ESP32 LT1210CT7
Electronic Components & Supplies 1: ESP8266
Electronic Components & Supplies 2: DIY KIT
Electronic Components & Supplies 3: DC-DC
Electronic Components & Supplies 4: STM32
Processing and Properties of Compound Semiconductors
The worldwide integrated circuits (ICs) market has reached more than a hundred billion dollars per year, where the majority of the IC chips sold are fabricated using silicon as the substrate material. The technology of silicon ICs, however, is approaching fundamental limits set by the atomic nature of matter.
One cannot count on doubling the chip capacity by shrinking the size of Si complementary metal-oxide-semiconductor (CMOS) devices forever, and many people expect that the Moore law will be invalid in 10–15 years. In the meantime, rapidly growing telecommunications industries are driving the development of reliable and economical high-frequency devices with lower-power dissipation.
Si/Si1-x Gex heterostructures are, therefore, under extensive study because they can provide adjustable bandgaps and improved carrier mobilities compared with Si homostructures. Heterojunction bipolar transistors (HBTs) that utilize Si/SiGe heterolayers promise a very impressive extension of the high-frequency limit of Si-based bipolar technology to cutoff frequencies well above 100 GHz, a frequency range that, so far, has been dominated by GaAs-based devices.
Modulation-doped LT1210CT7 field-effect transistors (MODFETs) that employ SiGe as the channel layer have also shown considerable improvement in both speed and gain over their Si counterparts. High-sensitivity photodetectors made with Si/SiGe have also been fabricated . Several quantum size effects in strained SiGe layers and their potential in device applications were reviewed by Karunasiri and Wang.
In the near future, Si/SiGe heterojunction and superlattice-based devices may even play an important role in the integration of complex electronic circuitry with optoelectronic functionality on a single IC chip. For example, growing GaAs on high-quality SiGe buffer layers on Si may combine laser diodes made of III-V materials with Si ICs.
Tensilely strained Si can also be grown on these SiGe buffer layers and improved surface-channel devices have been demonstrated. Si/SiGe LT1210CT7 heterostructures have, therefore, opened up a new, exciting avenue of research opportunities.
Fabrication processes for Si/SiGe devices are rather compatible with those routinely used for Si ICs, and this is a major advantage for Si/SiGe over compounds. This compatibility ensures the continued use of the existing multibillion-dollar Si IC fabrication facilities for the manufacture of Si/SiGe devices, which makes SiGe more cost effective than GaAs for technological evolution.
However, SiGe has its problems too. One of the most important problems in fabricating Si/SiGe devices is associated with the thermal stability of the heterostructures under various processing steps, such as ion implantation and postimplant annealing .
The intrinsic strain in a Si/SiGe heterostructure is, therefore, both a blessing and a curse. The presence of intrinsic pseudomorphic strain changes the band structure of Si/SiGe and can enhance the mobility of carriers. However, if strain relaxation takes place during annealing, unwanted defects are introduced and the performance of Si/SiGe devices will be degraded considerably.
To make millions of Si/SiGe transistors on a planar IC chip, one has to be able to process the heterostructure with great precision in a repeatable fashion and with a very low defect density level. In general, defects generated by advanced deep-submicrometer wafer processing can act as nucleation sites for dislocation formation, which is shown to enhance the undesired strain relaxation of SiGe.
High-temperature thermal treatment of Si/SiGe 950 °C can also introduce very significant interdiffusion of Ge and Si. Due to the problems of interdiffusion and strain relaxation, it is evident that processing of Si/SiGe devices requires a substantial decrease in the thermal budget over devices made of Si, which can make the manufacture of these devices difficult.
It is also challenging to design and control the exact Ge profiles in the devices. The epitaxial growth, etching, isolation, and salicidation modules required for Si/SiGe devices may also need to be redeveloped and reoptimized. All of these materials properties and processing issues are covered in Section 2.
There are many exciting and novel devices that can be built with Si/SiGe LT1210CT7 heterostructures, but, in our opinions, by far the most important device of all is the Si/SiGe HBT. Numerous new circuits and products just announced in the past few years use Si/SiGe HBTs. We discuss in detail the device physics and the design optimization for this important device in Section 3, where other devices such as Si/SiGe metal-oxide-semiconductor field-effect transistors (MOSFETs) also are discussed.
This review chapter is an up to date and comprehensive treatment on how and why the exciting Si/SiGe technology is so important to the advancement of the entire IC industry. From the basic discussions on the materials properties to real-life Si/SiGe circuits and products, we believe that no other single publication of this ambitious scope currently exists in the literature.
Hence, the one major reason for the format and content of this review chapter is to cover and explain the most important characteristics of this Si/SiGe technology and its applications. It was extremely challenging to make this chapter comprehensive and up to date because many new publications on this subject are appearing at a very fast pace.
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