Method of manufacture of group III nitride semiconductor

Abstract

A method for manufacturing a group III nitride semiconductor without causing adverse effects on device characteristics includes: preparing a group III nitride substrate having a first group III nitride layer and a second group III nitride layer laminated in this order from a back-surface side to a front-surface side, the first group III nitride layer being a layer having a transmittance of 60% or more for a predetermined wavelength of 400 nm to 700 nm, the second group III nitride layer being a layer provided on the first group III nitride layer and containing impurity oxygen in a concentration of 1×1020 cm−3 or more and having a transmittance of 0.1% or less for the predetermined wavelength; forming a device structure on the front-surface side of the group III nitride substrate; and forming an internal altered layer in the first group III nitride layer by multiphoton absorption using a laser beam applied from the first group III nitride layer side on the back-surface side of the group III nitride substrate with a focal point set in front of the second group III nitride layer, and dividing the group III nitride substrate at the internal altered layer serving as a boundary.

Dependencies are inferred from the claim text.