Indium gallium arsenic are now of considerable commercial importance in optoelectronics. For example HBT

HEMTs

FET and Detectors. Very high quality is required to fabricate these devices

in terms of electrical and optical properties. The epilayer properties are known to be very sensitive to growth parameters (growth temperature

Ⅴ/Ⅲ ratio

etc.). It is important to find suitable growth temperature for good quality epilayer properties. The effects of growth temperature on solid composition

surface morphology

crystal quality and electrical properties were investigated for InGaAs. In

0.53

Ga

0.47

As was grown by low-pressure metalorganic chemical-vapor deposition on semi-insulating Fe-doped InP substrate. The substrates were misoriented 2～5° toward (110). Precursors were trimethylindium(TMIn) and trimethylgallium(TMGa) for group Ⅲ

arsine(AsH

3

) and phosphine(PH

3

) for group Ⅴ. The growth temperatures ranged from 500～680℃. Before the epitaxy of InGaAs

an InP buffer layer was grown with 0.1μm. The composition of InGaAs was determined by X-ray diffraction. The surface morphology was examined with SEM. Electrical properties were investigated by Hall effect measurements at room-temperature. The mirror like and featureless morphology of In

0.53

Ga

0.47

As epilayer was attained. In order to keep indium solid composition constant

TMIn vapor composition increase with growth temperature increasing. The pyrolysis temperature of TMGa is higher than that of TMIn which pyrolyzed completely at 500℃. In the range of 500～650℃

the TMGa pyrolysis efficiency increase rapidly with increasing growth temperature. In the range of 650～680℃

because of a larger volatilization rate of indium from surface which is greater than that of gallium

the surface morphology became rough above 680℃. The FWHM of X-ray rocking curve is a good indication of the epilayer quality. A plot the X-ray rocking curve FWHM as a function of growth temperature show a low values between 630℃ and 650℃ but it rises at both higher and lower temperatures. The mobility increase with growth temperature increasing under 630℃. The mobility decrease with growth temperature increasing above 630℃.The best mobility can be obtained at 630℃. At low growth temperature the carrier concentration increase dramatically. This is attributed to enhance carbon incorporation.