Wafer separation technique for the fabrication of free-standing (Al,In,Ga)N wafers
OwnerJames Speck, Troy Baker +1inventors
InventorsJames Speck, Troy Baker, Benjamin Haskell
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Abstract
A method of fabricating free-standing (Al, In, Ga)N substrates, by in situ separation of thick epitaxially grown nitride films from their foreign substrates. A suitable substrate for (Al, In, Ga)N film growth is selected, and foreign ions are implanted in the substrate to form a comparatively sharp concentration profile. An (Al, In Ga)N film is deposited on the substrate, and the deposited film is cooled to introduce thermal expansion mismatch-related strain, so that the film spontaneously separates from the substrate.
Claims20
A method of in situ separation of epitaxially-grown nitride films from their foreign substrates, comprising:
- selecting a suitable substrate for (Al, In, Ga)N film growth;
- implanting foreign ions in the substrate to form a comparatively sharp concentration profile;
- growing a (Al, In, Ga)N film on the substrate;
- and
- cooling the film and substrate to introduce thermal expansion mismatch-related strain, wherein the film separates from the substrate spontaneously.
A method for in situ fabrication of a free-standing wafer, comprising:
- (a) providing a substrate having a concentration profile of foreign ions below a surface of the substrate;
- (b) depositing a film on the surface of the substrate;
- and
- (c) cooling the substrate and film to introduce thermal expansion mismatch-related strain, wherein the film on top of a membrane that is a fragment of the substrate spontaneously separates from the substrate along the concentration profile, in order to create a free-standing wafer.
Dependencies are inferred from the claim text.