GaAs vs InP: Choosing the Right III-V Substrate

Short answer: Choosing between gallium arsenide (GaAs) and indium phosphide (InP) comes down to wavelength and frequency: GaAs is the workhorse for RF power amplifiers, MMICs, and shorter-wavelength optoelectronics (around 850 nm), while InP is the required platform for long-haul fiber-optic components operating at 1310 nm and 1550 nm, and for the highest-frequency electronics. GaAs substrates are more mature, available in larger diameters, and cost less; InP delivers higher electron velocity and direct-bandgap emission at telecom wavelengths that GaAs cannot reach.

Mihron Metalyx, Toronto’s III-V substrate distributor, stocks and sources both platforms so engineers can match the material to the wavelength or frequency spec rather than what happens to be on the shelf. See our wafer specifications guide for full property tables.

When should you choose GaAs?

GaAs suits applications where cost, substrate maturity, and moderate frequency dominate: RF power amplifiers for handsets and base stations, MMICs, VCSELs for short-reach datacom (850 nm), LEDs, and space-grade photovoltaics. Semi-insulating GaAs substrates support monolithic microwave circuits, and the supply chain is deep — substrates are available up to 6" with well-established epi processes.

When is InP the right platform?

InP is the default wherever 1310/1550 nm telecom wavelengths or extreme speed are involved: laser diodes and photodetectors for long-haul and metro fiber networks, coherent optics, photonic integrated circuits (PICs), and HEMT/HBT electronics pushing past 100 GHz. Its higher electron velocity also makes it the choice for the fastest transistors and for emerging co-packaged optics in AI data centers — a demand driver that has tightened InP substrate supply.

GaAs vs InP at a glance

What about GaSb, InAs, and InSb?

For infrared work beyond InP's range, the antimonide/arsenide family takes over: GaSb substrates anchor mid-IR lasers and thermophotovoltaics, InAs supports mid-IR detectors and quantum structures, and InSb delivers the highest electron mobility of any common III-V — the basis of magnetic sensors and long-wave IR detectors. Mihron Metalyx sources all three alongside GaAs and InP.

Sourcing III-V substrates in North America

Mihron Metalyx supplies GaAs (semi-insulating, n-type, p-type), InP (SI, n-type, p-type), and GaSb/InAs/InSb substrates in 2"–6" diameters, epi-ready, VGF and LEC grown, from a bonded Toronto warehouse at 2967 Dundas St. W. #141B, Toronto. Every lot ships with a Certificate of Analysis, and quotes return within 48 hours. Current per-wafer costs are on our wafer pricing guide.

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Frequently asked questions

Is GaAs or InP better for fiber-optic components?

InP. Long-haul and metro fiber networks operate at 1310 nm and 1550 nm, wavelengths that require InP-based lasers and photodetectors with lattice-matched InGaAsP or InGaAs epitaxy. GaAs emits around 850 nm and is limited to short-reach links.

Which substrate should I use for RF power amplifiers?

GaAs for most PA applications up to tens of GHz — it is the mature, cost-effective choice for handset and base-station PAs and MMICs. InP HEMTs and HBTs take over when designs push beyond roughly 100 GHz.

Can I get semi-insulating GaAs and InP in Canada?

Yes — Mihron Metalyx stocks and sources semi-insulating, n-type, and p-type GaAs and InP substrates from a bonded Toronto warehouse, shipping across Canada and the US in 3–5 business days for stock material.