Gallium arsenide can be made into semi insulating high resistance materials with a resistivity of more than 3 orders of magnitude higher than that of silicon, which can be used to make integrated circuit substrates, infrared detectors γ Photon detector, etc. Because its electron mobility is 5 ~ 6 times higher than that of silicon, it has the advantages of good performance at high frequency, high temperature and low temperature, low noise and strong radiation resistance，Although Gallium Arsenide have many advantages, gallium arsenide will not replace silicon as the mainstream semiconductor material.
The reason lies in the trade-off between performance and manufacturing difficulty. Although GaAs circuits are very fast, most electronic products do not need to be so fast. In terms of performance, gallium arsenide, like germanium, has no natural oxide. For factory compensation, multilayer insulators must be deposited on GaAs. This will result in longer process time and lower production. And half of the atoms in gallium arsenide are arsenic, which is very dangerous to human beings. Unfortunately, arsenic will evaporate at normal process temperature, which requires additional inhibition layer or pressurized process reaction chamber. These steps extend the process time and increase the cost.
It is easy to break in the process, and it also leads to the production level of large-diameter GaAs lagging behind that of silicon.
Despite these problems, GaAs is still an important semiconductor material, its applications will continue to increase, and may have a great impact on the performance of computers in the future.
Silicon germanide (SiGe) is a competitive material with gallium arsenide This combination increases the speed of transistors to Cho for application in ultra-high speed walkie talkies and personal communication equipment. . The structural feature of devices and integrated circuits is the deposition of germanium layers by ultra-high vacuum / chemical vapor deposition (UHV / CVD). Bipolar transistors are formed in germanium layer VII. Different from the simple transistors formed in silicon technology, silicon germanide requires transistors to have heterostructures and heterojunctions. These structures have several layers and specific doping levels, so as to allow high-frequency operation. The comparison column between two main semiconductor materials and silicon dioxide.