Wafers and substrates
Semiconductor Wafer Selection Guide
A wafer inquiry should describe both the bulk crystal and the surface supplied to the process. Material and diameter alone are not enough to confirm a compatible substrate.
Crystal and orientation
Specify the substrate material, crystal orientation and any intentional offcut. State the required flat or notch convention when it must match equipment or process identification.
Electrical specification
Define undoped, n-type, p-type or semi-insulating material as applicable. Include dopant, resistivity or carrier concentration range when the electrical behaviour matters.
- Conductivity type
- Dopant
- Resistivity range
- Carrier concentration
- Mobility if required
Mechanical and surface specification
Diameter, thickness and total-thickness variation should be agreed together with single- or double-side polishing, epi-ready finish and backside condition.
- Diameter and thickness
- TTV, bow and warp where critical
- SSP or DSP
- Epi-ready requirement
- Edge and backside finish
Epitaxial structures
For templates or epitaxial wafers, provide the complete layer stack, thickness, composition, doping and substrate definition. A device sketch or previous specification is often the clearest reference.