InGaAs

If was nof until fhe developmenf of Fourier fransform infrared (FTIR) specfromefers (see Section 3.3.3.2) fhaf fhe possibilify of using an infrared laser routinely was opened up. The intensify advanfage of an infrared interferometer, wifh which a single specfrum can be obfained very rapidly and fhen many specfra co-added, coupled wifh fhe developmenf of more sensitive Ge and InGaAs semiconductor infrared defectors, more fhan compensate for fhe loss of scatfering intensify in fhe infrared region. 

In photodetectors (qv) for photocouplers, optical switches, fiber optics, communication, and imaging, the materials used are InGaAs, InGaAsP, and... 

An extensive compilation of the properties of compound semiconductors may be found in the Landolt-Bn mstein reference books (13,14). Various subvolumes in the series cover the properties of elemental. III—V, II—V, and other less common semiconductors. Information may also be found concerning semiconductor technology. Another useful source of information is the EMIS data review series (15). These books describe the properties and technology of GaAs, HgCdTe, InP, AlGaAs, InGaAs, and the III—V nitride compounds. 

A powerful feature of wet etching is the abiUty to achieve excellent etch selectivities of one material over another. This can be extremely useful in the fabrication of epitaxial devices with different material layers. Because selective etching allows the removal of specific layers, the final accuracy of the etch can approach that of the epitaxial layers. Etch selectivities of >100 1 have been achieved for citric acid H202 etching of GaAs—AlGaAs and InGaAs—InP stmctures (133). 

V semiconductor material (e.g. InGaAs semiconductor). Very high purity Ga and In are required for the manufacture of semiconductor grade GaAs substrate material and in the deposition of the III—V alloy epilayer structures on these substrates, for example for the manufacture of laser diodes. 

The production of emitting sources requires further development in material technology, as the emitting wavelength is controlled by the compositions of alloy semiconductors to form heterostructures such as InGaAs/InAs" " or III-V alloy systems. 

InP/InGaASP long-wavelength lasers and detectors InP/InGaAs quantum wells, solar cells, detectors GaAs on Si wafers GaAs/InGaP HBTs... 

The conventional method of CVD growth of In-V thin films is to use indium alkyl precursors (Table 8), preferably Me3In. However, early problems in the growth of InP and InGaAs were... 

Silicon photodiodes exhibit maximum sensitivity at about 800 nm and they can be used in the whole visible range however their sensitivity drops by several times at the blue region. Special structures can be made with enhanced blue sensitivity (so-called blue or UV diodes). Germanium photodiodes are capable to detect radiation from 600 nm up to 1700 nm. In telecommunication applications InGaAs elements are widely used. 

Optical receiver noise can arise partly from fundamental photon noise and partly from thermal noise in the receiver circuit. For CO2 detection, it was assumed that the optical receiver was an extended InGaAs detector, followed... 

---