Xiamen Powerway Advanced Material Co.,Ltd., a leading supplier of AlGaAs layer 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 AlGaAs layer to our customers including many who are developing better and more reliable for GaAs-based red- and near-infra-red-emitting (700 nm-1100 nm) double-hetero-structure laser diodes. Our AlGaAs layer has excellent properties, it’s used as a barrier material in GaAs based heterostructure devices. The AlGaAs layer confines the electrons to a gallium arsenide region. An example of such a device is a quantum well infrared photodetector (QWIP). The availability improves 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 AlGaAs layer are natural by products of our ongoing efforts, currently we are devoted to continuously develop more reliable products.”
PAM-XIAMEN’s improved AlGaAs product line has benefited from strong tech. support from Native University and Laboratory Center.
Now it shows an example as follows:
1. Epitaxial Structures of AlGaAs Layer on GaAs Substrate
Structure 1:
3” AlGaAs/GaAs/AlGaAs on GaAs substrate
thickness of each epilayer 1μm
dopant density for GaAs layer 10^17-10^18 /cm3
Al_xGa_1-xAs stoichiometry x~0.3
Structure 2: AlGaAs Epi Layer Structure (PAM-P20071-ALGAAS)
1 GaAs, (100), 50±2.5 nm in thickness
2 AlxGa1-xAs device layer, (100), 1±0.05 μm in thickness, x = 0.15 ~ 0.168, rms roughness < 0.5 nm
3 InxGa1-xP, (100), 100±5 nm in thickness, x = 0.49
4 GaAs, (100), 100±5 nm in thickness
5 InxGa1-xP, (100), 100±5 nm in thickness, x = 0.49
6 GaAs substrate, 350 mm
Major flats: based on EJ flat
Primary flat (0-1-1), 17mm
Secondly flat (0-1 1) 7mm
Remark:
Oxygen content <2E16 in the AlGaAs layers;
If you want RMS Roughness<0.5nm, substrate (100)off 10deg. is suggested, rather than on axis (100), because the growth quality and surface roughness of GaInP of high off axis substrate are better than that of orthorhombic substrate, while AlGaAs is almost the same on different deflection substrates.
Structure 3: AlGaAs Epitaxial Wafer (PAM170223-ALGAAS)
Structure from bottom to top:
Layer0: Substrate:2″ GaAs substrate (100)
Layer1: 4 microns of AlxGa1-xAs (the lower cladding),
Layer2: 1.5 microns of AlxGa1-xAs (the core)
Layer3: 1.5 microns of AlxGa1-xAs (the upper cladding)
Remark:
Peak PL wavelengths=770.7nm, but we can reduce the peak PL wavelength slightly to ~753 nm, ie. X = 0.18 if necessary
Structure 4: AlGaAs / GaAs Wafer (PAM160613-ALGAAS)
| Layer No. | Material | Thickness | Concentration |
| 6 | n-GaAs (Si) | – | – |
| 5 | graded n-Al0.1Ga0.7As (Si) | – | 5×1017cm-3 |
| 4 | n-AlxGa1-xAs (Si) | – | – |
| 3 | graded n-Al0.1Ga0.7As (Si) | 30nm | – |
| 2 | p-GaAs (C) | – | – |
| 1 | AlAs (Si) | – | – |
| GaAs Substrate |
2. GaAs/AlGaAs Structure
This structure is the most studied and mature III-V compound system, and it is one of the most basic materials in modern optoelectronic technology. Through the study on GaAs epitaxial growth, we found the main reason for the development of this material system is that AlGaAs has a lattice matching with GaAs in the full composition range, and has a large energy gap difference △Eg. Moreover, various heterojunctions, quantum wells and superlattice structures can be prepared by this structure, and it is convenient to adjust the A1 component to produce the desired wavelength. At the same time, due to the large refractive index difference between AlGaAs and GaAs, AlGalAs/GaAs is widely used to make distributed Bragg reflectors (DBR), which greatly improves the device performance of surface emitting lasers, high-brightness light-emitting diodes, and microcavity resonant light-emitting diodes. However, it has a serious shortcoming “Al”. Aluminum is particularly susceptible to oxidation on the high-temperature end surface, leading to COD production. Therefore, the high-power output cannot be restricted.
3. About AlGaAs Material
Aluminium gallium arsenide (also gallium aluminium arsenide) (AlxGa1−xAs) is a semiconductor material with very nearly the same lattice constant as GaAs, but a larger bandgap. The x in the formula above is a number between 0 and 1 – this indicates an arbitrary alloy between GaAs and AlAs. The formula AlGaAs should be considered an abbreviated form of the above, rather than any particular ratio. The bandgap varies between 1.42 eV (GaAs) and 2.16 eV (AlAs). For x < 0.4, the bandgap is direct. The refractive index is related with the bandgap via the Kramers–Kronig relations and varies between 2.9 (x = 1) and 3.5 (x = 0). This allows the construction of Bragg mirrors used in VCSELs and RCLEDs.
4. Q&A about AlGaAs Epi Layer Stacked on GaAs Wafer
Q1: I”m looking for some GaAs wafers with a custom epilayer stack of AlGaAs/GaAs/AlGaAs grown on top 2” and 3″ wafers with each epilayer having a thickness of order 1 micron Si-doped at Na in the range 10^17-10^18 /cm3 for both the GaAs and barrier layers, with Al_xGa_1-xAs stoichiometry x~0.3
A: Yes, it could be supplied
Q2: The quote you gave us was for a 220nm layer of GaAs on top with a 2µm thick Al_0.7 Ga_0.3 As layer.We are now interested in purchasing a 250nm GaAs layer on top of a 3µm thick Al_0.7 Ga_0.3 As layer.Would you be able to manufacture such wafers?
A: Yes, we could supply both of above wafers.
Q3: What is the thickness tolerance for the top GaAs layer of GaAs/AlGaAs epi wafer below?
GaAs layer
Al0.8Ga0.2As
2″ GaAs substrate (backside polished)
A: The standard error for the top GaAs layer of AlGaAs epi wafer in thickness is about 3%.
Q4: May I know what is the measured or estimated roughness value if AlGaAs is grown on on-axis (100) of GaAs?
A: The estimate surface roughness of AlGaAs layer epitaxial on orthorhombic GaAs (100) substrate is ~1.5nm.
For more information, please contact us email at victorchan@powerwaywafer.com and powerwaymaterial@gmail.com