Material Properties and Applications of Aluminium Gallium Arsenide (AlGaAs)
Aluminium Gallium Arsenide (AlGaAs) is a semiconductor material with very nearly the same lattice constant as GaAs, and it is an arbitrary alloy between GaAs and AlAs.
GaAs has the large lattice constant, and AlGaAs is grown on the GaAs substrate without lattice mismatches using molecular-beam-epitaxy (MBE) or metal-organic-chemical-vapor-deposition (MOCVD).
Optoelectronics are one of the major applications of AlGaAs, including vertical-cavity-surface-emitting-lasers (VCSELs), laser-diodes (LDs) and infrared light-emitting-diodes (LEDs).
Another application can be seen in telecommunication. Heterojunction-bipolar-transistors (HBTs) are fabricated using epitaxial AlGaAs/GaAs layers. AlGaAs/GaAs HBTs exceed silicon bipolar transistors in switching speed.
AlGaAs/GaAs Etching for VCSEL
There are several requirements for AlGaAs/GaAs etching process in VCSEL fabrication.
· Etch depth control
· Non-selective etching between AlGaAs/GaAs
· Smooth and vertical sidewalls
· Clean surfaces
The etched profile showed smooth and vertical surfaces.
Using an end-point detection system improves preciseness of etch depth control.
AlGaAs Array Fabrication for LED
AlGaAs arrays were fabricated for LED production using chlorine chemistry.
Etch Depth : 60 µm
Etch Rate : 1.54 nm/min
Etch Mask : gold