GaAs/AlAs Wafer

GaAs/AlAs Wafer

From a solid-state device perspective, aluminum arsenide (AlAs) has great potential, especially because alloys of AlAs and GaAs can provide material for high-speed electronic and optoelectronic devices. Moreover, GaAs / AlAs quantum well structures are widely used in the fabrication of III-V epitaxial wafer. For GaAs / AlAs short-period superlattices, the absorbance is greatly improved, which expands in the visible light. Therefore, it is also an ideal material for optoelectronic devices (like high light emitting diode). PAM-XIAMEN provides wafer of N+ or P+ GaAs epi with AlAs layer on N+ or P+ GaAs substrate as follows:

GaAs / AlAs wafer

1. Specs of GaAs-AlAs Heterostructures

No.1 spec: 2-inch p+ GaAs Epi with AlAs layer on p+ GaAs substrate

Epi Structure (from bottom to top):

Layer0: 350 um p+ semi-conducting GaAs substrate, >E18 doping, any dopant type

Layer1: 300 nm p+ semi-conducting GaAs buffer layer, >E18 doping concentration, any dopant type

Layer2: 10 nm AlAs undoped (the AlAs layer must be grown using As2 [dimer] and NOT As4 [tetramer]),

Layer3:  2 um p+ semi-conducting GaAs epi layer, >E18 doping concentration, any dopant type


No.2 spec:  2-inch n+ GaAs Epi with AlAs layer on n+ GaAs substrate

Structure (from bottom to top):

Layer0: 350 um n+ semi-conducting GaAs substrate, Si-doping with >E18 doping

Layer1: 300 nm n+ semi-conducting GaAs buffer layer, Si-doping with >E18 doping concentration

Layer2: 10 nm AlAs undoped (the AlAs layer must be grown using As2 [dimer] and NOT As4 [tetramer]),

Layer3: 2 um n+ semi-conducting GaAs epi layer, Si-doping with >E18 doping concentration


No.3 spec: 2-inch GaAs – AlAs two-barrier structure:

1 layer: contact, GaAs, carrier concentration 10e18 cm-3, 100 nm

2 layer: spacer, GaAs, undoped, 10 nm

3 layer: barrier, AlAs, undoped, 2, 3 nm

4 layer: quantum well, GaAs, undoped, 4, 5 nm

5 layer: barrier, AlAs, undoped, 2 nm

6 layer: spacer, GaAs, undoped, 40 nm

7 layer: contact, GaAs, carrier concentration 10e18 cm-3, 500 nm


No. 4  n-GaAs/AlAs/GaAs Epi Wafer for MESFET Device Fabrication

• High quality (100) Si-doped n-type GaAs layer with (carrier concentration of 4.0x10E17 cm-3 ) thickness: 120nm
• bilayers SI-GaAs thickness: 150nm
• / AlAs thickness: 200nm
• / Semi insulating SI-GaAs substrate. thickness: 350+/-25um


No.5 spec: 20nm undoped GaAs/10nm AlAs on GaAs S.I. substrate (No DRAM, no SRAM, no memory chips – wafers only).

2. Anisotropy of the Thermal Conductivity in GaAs-AlAs Superlattices

We combine the transient thermal grating and time-domain thermoreflectance techniques to characterize the anisotropic thermal conductivities of GaAs/AlAs superlattices from the same wafer. The transient grating technique is sensitive only to the in-plane thermal conductivity, while time-domain thermoreflectance is sensitive to the thermal conductivity in the cross-plane direction, making them a powerful combination to address the challenges associated with characterizing anisotropic heat conduction in thin films. We compare the experimental results from the GaAs/AlAs superlattices with first-principles calculations and previous measurements of Si/Ge SLs. The measured anisotropy is smaller than that of Si/Ge SLs, consistent with both the mass-mismatch picture of interface scattering and with the results of calculations from density-functional perturbation theory with interface mixing included.

3. Temperature Dependence of GaAs / AlAs thin-film Structures

We use ac calorimetric method to measure the temperature dependence for thermal physical properties of GaAs / AlAs material system. The thermal diffusion of GaAs / AlAs heterojunction at 700 Å/700 Å is tested from 190K to 450K through our experiment. We obtained the result that the thermal diffusion of GaAs / AlAs heterostructure is lower than the corresponding bulk value. And its thermal physical properties are little temperature dependence than that of bulk III-V compounds. The main reason for decreasing thermal conductivity is interface scattering.

4. Study on Reactive Ion Etching Rate of GaAs, AIAs, DBR

We use BCl3 and Ar as the etching gas to study the reactive ion etching process of GaAs, AlAs and DBR. During the experiment, the RF power and gas composition have a great influence on the etching rate, while there is little effect of the total amount of gas and pressure. Under certain conditions, the etching rate of GaAs can be greater than 400nm/min, the etching rate of AlAs can reach 350nm/min, and the etching rate of DBR can reach 340nm/min. After etching, the surface is relatively smooth, which can form a relatively steep side wall, and the vertical degree of the side wall can reach 85°.

Source: PAM-XIAMEN, American Chemical Society

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