Low Temperature Grown InGaAs (LT-InGaAs)

Low Temperature Grown InGaAs (LT-InGaAs)

PAM-XIAMEN offers low temperature grown InGaAs (LT-InGaAs) on GaAs Substrate for InGaAs Photo Conductive antenna substrate for THz, excitation wavelength will be 1030 nm. Low-temperature-grown In0.53Ga0.47As on GaAs is grown at low temperature using gaseous molecular beam epitaxy technology, and the effects of different growth temperatures and arsine pressures on the quality of the epitaxial layer are studied by high-resolution X-ray diffraction technology, which optimize the molecular beam epitaxial growth process. At the same time, the p-type acceptor Be was introduced into InGaAs to compensate the carrier concentration to increase the dark resistance of the material. Finally, a good quality low-temperature InGaAs  / InAlAs superlattice and sheet resistance were obtained, reaching 1.63×106Ω/□. High quality epitaxial thin film stacks using the InGaAs on GaAs wafer covered with memtallic contacts can be used in different applications.


1. Specifications of LT-InGaAs on GaAs Substrate

2″ LT-InGaAs Wafer (PAM210129-LT-INGAAS)
Diameter(mm)Ф 50.8mm ± 1mm
Thickness 0.5-3um
Useable Surface Area≥90%
Polishing: Single side polished
Structure: LT-InGaAs on GaAs
Substrate: GaAs substrate
In composition from 0.05 to 0.40

In addition, we can offer LT-GaAs(low temperature grown GaAs on GaAs Substrate), please below detail spec:

2″ LT-GaAs Wafer Specification
Diameter(mm)Ф 50.8mm ± 1mm
Thickness 1-2um
Marco Defect Density≤5 cm-2
Resistivity(300K) >10^8 Ohm-cm
Carrier lifetime<15ps or <1ps
Dislocation Density<1×106cm-2
Useable Surface Area≥80%

Polishing: Single side polished
Substrate: GaAs substrate

2. Growth Process for GaAs-based LT InGaAs Epi Wafer

The low-temperature InGaAs material was grown by gas source molecular beam epitaxy (GSMBE), and the influence of growth temperature and As pressure on the properties of InGaAs was studied. The growth conditions were optimized: the InGaAs growth temperature was 300℃ and the As pressure was 580 Torr. Through Be doping and using In0.52Al0.48As/In0.53Ga0.47As multiple quantum well structure, the resistance of the InGaAs wafer is increased to 1.632 x 106/sq, and the carrier concentration is reduced to 1.058 x 1014 cm-3. XRD shows that InGaAs multiple quantum well materials have higher crystal quality. This Be-doped InGaAs multiple quantum well material has high trap density and high resistivity.

Since InAlAs has a high concentration of deep electron traps, the electrons in the InGaAs layer can be trapped by the deep electron traps of InAlAs through the tunneling process, so that the dark resistivity of the material is greatly improved. For undoped low-temperature InGaAs epi-layer, the carrier concentration does not decrease much when the multiple quantum well structure is used. This may be due to the high electron concentration of undoped InGaAs. The limited deep electron trap density in InAlAs, and the trapped electrons have reached saturated state, so that the carrier concentration does not decrease much. It can also be seen that the use of a multi-quantum well structure hardly affects the mobility of carriers. The following table shows the electrical properties of indium gallium arsenide grown at low temperature:

Electrical characterization of various low-temperature InGaAs materials

Material N(cm-3) Mobility(cm2/V-s) Rs(ohm/sq)
LT InGaAs 1.615 x 1017 4680 109.3
LT InGaAs MQW 1.25 x 1017 4220 168.3
LT InGaAs: Be 1.708 x 1015 598 7.73 x 104
LT InGaAs: Be MQW 1.058 x 1014 517 1.632 x 106


However, the material will introduce high-concentration point defects related to excess As when growing InGaAs at low temperature. These point defects act as recombination centers, greatly reducing the lifetime of carriers. Then the activation energy of the defect energy level produced by these low-temperature growth is low, and low-temperature InGaAs has high electrical conductivity. One way to improve resistivity is to replace the Ga sites with Be doping to compensate for the AsGa anti-site defects introduced by excess As. In addition, adding a thin InAlAs layer to form an LT InGaAs-InAlAs QWs structure can further reduce the material response time and increase the material resistivity. 

For more information, please contact us email at victorchan@powerwaywafer.com and powerwaymaterial@gmail.com.

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