Aluminium gallium arsenide epi wafer (AlGaAs or AlxGa1−xAs) is a semiconductor wafer 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 chemical formula AlGaAs should be considered an abbreviated form of the above, rather than any particular ratio.
The bandgap of Aluminium gallium arsenide: 1.42 eV (GaAs) ~2.16 eV (AlAs). For x < 0.4, the bandgap is direct.
The refractive index of Aluminium gallium arsenide: 2.9 (x = 1) ~3.5 (x = 0), which allows the construction of Bragg mirrors used in VCSELs and RCLEDs.
Aluminium gallium arsenide wafer is used for heterostructure devices such as quantum well infrared photodetector (QWIP), VCSELs, RED LED wafer, red double-hetero-structure laser diodes or HEMT wafers, below two structures is detail application:
1.AlGaAs/GaAs wafer structure: PAM190529-ALGAAS
GaAs (10 nm)
AlGaAs (100 nm) with 30% Al and 70% Ga, doped at 1E18 cm^-3
Undoped AlGaAs (15 nm) (30% Al and 70% Ga)
GaAs (500 nm)
Remark: we can test mobility and 2DEG concentration.
2.AlGaAs/InGaAs/GaAs HEMT wafer PAM190510-HEMT
3.Al rich AlxGa1−xAs PAM200827-EPI
Al content x=0.5, 0.6, 0.8. Al-rich AlxGa1−xAs wafers on GaAs substrate, thickness:500nm, 2″size
Remark: High Mobility:~6000cm2/V.s, 2DEG density- Ns:2-3E12/cm2