US 8,012,882 B2 · Method of manufacturing nitride substrate for semiconductors

Abstract

In an independent GaN film manufactured by creating a GaN layer on a base heterosubstrate using vapor-phase deposition and then removing the base substrate, owing to layer-base discrepancy in thermal expansion coefficient and lattice constant, bow will be a large ±40 μm to ±100 μm. Since with that bow device fabrication by photolithography is challenging, reducing the bow to +30 μm to −20 μm is the goal. The surface deflected concavely is ground to impart to it a damaged layer that has a stretching effect, making the surface become convex. The damaged layer on the surface having become convex is removed by etching, which curtails the bow. Alternatively, the convex surface on the side opposite the surface having become convex is ground to generate a damaged layer. With the concave surface having become convex due to the damaged layer, suitably etching off the damaged layer curtails the bow.

Claims12

Dependent claims

A method of minimizing bow H in an as-grown GaN substrate, the method comprising:

a grinding step of mechanically grinding the as-grown GaN substrate to induce into at least either its front or its back side a damage layer in which the crystalline structure of the substrate is transformed, with a grit selected to smooth the ground side of the substrate yet leave the damage layer being of thickness sufficient to stretch the ground side so as to reduce the substrate bow H to be within +30 μm≧H≧−30 μm;
and
an etching step of either wet-etching or dry-etching the ground side of the substrate to remove enough of the controlled-thickness damage layer such as to further reduce the bow H to be within +30 μm≧H≧−20 μm.

Dependencies are inferred from the claim text.

Method of manufacturing nitride substrate for semiconductors

Life of this patent

Method of manufacturing nitride substrate for semiconductors

Life of this patent

Abstract

Claims12