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Home > News > PAM-XIAMEN Offers LT-GaAs epi layer for terahertz application
Xiamen Powerway Advanced Material Co.,Ltd., a leading supplier of LT-GaAs and other related products and services announced the new availability of size 2”-3”  is on mass production in 2017. This new product represents a natural addition to PAM-XIAMEN's product line.

Dr. Shaka, said, "We are pleased to offer LT-GaAs epi layer to our customers including many who are developing better and more reliable for laser device. Our LT-GaAs epi layer has excellent properties, GaAs films with low-temperature GaAs (LT-GaAs) layers were grown by molecular beam epitaxy (MBE) method on vicinal Si substrates oriented 6°off towards [110]. The grown structures were different with the thickness of LT-GaAs layers and its arrangement in the film. Investigations of crystalline properties of the grown structures were carried out by the methods of f X-ray diffraction (XRD) and transmission electron microscopy (TEM). The availability improve boule growth and wafering processes." and "Our customers can now benefit from the increased device yield expected when developing advanced transistors on a square substrate. Our LT-GaAs epi layer are natural by products of our ongoing efforts, currently we are devoted to continuously develop more reliable products."
 
PAM-XIAMEN's improved LT-GaAs product line has benefited from strong tech. support from Native University and Laboratory Center.
 
Now it shows an example as follows:
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<1x10^6cm-2
Useable Surface Area≥80%
Polishing: Single side polished
Substrate: GaAs substrate
 
About Xiamen Powerway Advanced Material Co., Ltd
 
Found in 1990, Xiamen Powerway Advanced Material Co., Ltd (PAM-XIAMEN) is a leading manufacturer of compound semiconductor material in China. PAM-XIAMEN develops advanced crystal growth and epitaxy technologies, manufacturing processes, engineered substrates and semiconductor devices. PAM-XIAMEN's technologies enable higher performance and lower cost manufacturing of semiconductor wafer.
 
About LT-GaAs
 
Low-temperature GaAs is known from the literature [13,14] has a lattice constant larger than the lattice constant of high temperature GaAs. This is due to the adsorption of excess As at low temperatures. There are stresses at the interface of LT-GaAs / GaAs due to the difference in lattice parameters. To reduce the accumulated stress the presence of misfit dislocations lying in the interface is required. The most profitable way to the formation of such misfit dislocations is bending the existing threading dislocations, the so-called process without activation. On the TEM images can be seen that in the annealed samples with a 700 nm LT-GaAs layer the dislocations are partly bent along the interface of LT-GaAs/GaAs (figure 2 (b)) and in the samples without annealing the dislocations are changing its direction of propagation at the interface (figure 4 (a)). However in the samples with 170 nm and 200 nm LT-GaAs layers such the features are observed much less often (figure 2 (с) and 4 (b)). Therefore, with increasing the LT-GaAs layer thickness the stresses at the interface of LTGaAs/GaAs are increasing and the dislocations are bent more effectively. In addition worth noting that position of LT-GaAs layer in the GaAs/Si(001) film did not play a significant role in changing the density of threading dislocations.
 
The crystalline perfection of the GaAs films with LT-GaAs layers and the GaAs films without ones was comparable. In the GaAs/Si structures with LT-GaAs layers the crystal lattice rotation round the direction was detected. It was found that in the LT-GaAs/Si layers the arsenic clusters are formed, as it occurs in the LT-GaAs/GaAs system without dislocation. It is shown that large clusters are formed mainly on the dislocations. It means the dislocations are a kind "channels" for atoms of As. Using δ-In we managed to obtain an ordered array of As clusters. The clusters array proved to have no effect on the density and the propagation path of threading dislocations. Thus, the dislocations affect the position and size of As clusters, and the clusters do not affect the evolution of the threading dislocations system. With increasing LT-GaAs layer thickness the stresses at the interface of LTGaAs/GaAs are increasing and the dislocations are more bent.
 
Q&A
Q: What’s the structure please? Is LT-GaAs layer grown on the GaAs substrate?
A: Yes, structure is GaAs/LT-GaAs.
 
Q: What is the band that the LT-GaAs corresponds to?
A: 800nmAlGaAs

Q: What’s the carrier lifetime?
A: Lifetime <15ps or <1ps
 
Q: We bought LT GaAs on GaAs wafer from you more than 1 year ago. We like the quality of your LT GaAs, but for our experiments, we need to transfer LT GaAs to other substrate (quartz etc.).Can you grow AlAs then LT GaAs on semi-insulating GaAs wafer so that we can layer transfer LT GaAs?
A: Please just give me the structure and layer thickness, so that we can check.
 
Q: I think what we want is(from bottom up) GaAs substrate/AlAs(300nm)/LT GaAs (1-2um).
A: Yes we can grow this structure with AlAs300nm.
 
 For more information, please visit our website: http://www.powerwaywafer.com, send us email at angel.ye@powerwaywafer.com or powerwaymaterial@gmail.com.