The orientation of semiconductor crystals and wafers as determined by these test methods is an important materials acceptance requirement because the orientation controls various parameters of semiconductor devices fabricated from the material.

This Test Method covers techniques for determining the crystallographic orientation of a surface which is roughly parallel to a low-index atomic plane in single crystals used primarily for semiconductor devices.

Two types of test methods are covered as follows:

Test Method A, X-Ray Diffraction Orientation — This test method may be used for the orientation of all semiconductive single crystals. The X-ray test method is nondestructive and yields the more precise measurement of orientation; however, use of the equipment requires compliance with stringent safety regulations.
Test Method B, Optical Orientation — This test method is limited in application at the present time to elemental semiconductors. The optical test method requires etching the specimen and is therefore destructive of polished wafer surfaces. This test method is less precise than the X-ray test; however, the apparatus required is less complex.

Referenced SEMI Standards (purchase separately)
SEMI C28 — Specification for Hydrofluoric Acid
SEMI C30 — Specification for Hydrogen Peroxide
SEMI C40 — Specification for Potassium Hydroxide, 45% Solution
SEMI C43 — Specification for Sodium Hydroxide, 50% Solution

Revision History
SEMI MF26-0714E (Reapproved 1023)
SEMI MF26-0714E (editorial revision)
SEMI MF26-0714 (technical revision)
SEMI MF26-0305 (Reapproved 0211)
SEMI MF26-0305 (technical revision)
SEMI MF26-87a (Reapproved 1999) (first SEMI publication)