Thermal Oxide or SOI? Choosing an Insulating Substrate

Both structures put an oxide layer in your process, but they serve different purposes.

Thermal oxide wafers have SiO₂ grown on top of the silicon. They suit isolation layers, dielectric studies and transfer substrates for 2D materials. They are economical and fast to produce.

SOI wafers bury the oxide under a thin, single-crystal silicon device layer. The buried oxide works as an etch stop and as electrical isolation, which makes SOI the standard choice for many MEMS and silicon photonics designs.

Not sure which one you need? Send us a sketch of your process flow and we will suggest a stack.