Methods of making substrate structures having a weakened intermediate layer
AssigneeSoitec
InventorsMichel Bruel, Bernard Aspar, Chrystelle Lagahe-Blanchard
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Abstract
This invention provides composite semiconductor substrates and methods for fabricating such substrates. The composite structures include a semiconductor substrate, a semiconductor superstrate and an intermediate layer interposed between the substrate and the superstrate that comprises a material that undergoes a structural transformation when subject to a suitable heat treatment. The methods provide such a heat treatment so that the intermediate layer becomes spongy or porous, being filled with numerous micro-bubbles or micro-cavities containing a gaseous phase. The composite semiconductor substrates with structurally-transformed intermediate layers have numerous applications.
Claims20
A method for fabricating a composite semiconductor structure, the method comprising:
- providing an initial composite structure comprising at least one intermediate layer interposed between a substrate and a superstrate, the substrate and a superstrate comprising the same or different semiconductor materials, and the intermediate layer comprising a CVD-deposited glass material having a composition whereby, when subjected to a suitable heat treatment, the material undergoes a structural transformation becoming spongy;
- and
- applying a suitable heat treatment to the initial composite structure at a temperature in the range from 900° C. to 1200° C. so that the as-deposited intermediate layer becomes spongy consequent to the structural transformation,
- wherein the glass material comprises silicon oxide doped with phosphorous or silicon oxide doped with phosphorous and boron, and
- wherein the spongy transformation comprises the formation of microbubbles or microcavities containing a gaseous phase.
A method for fabricating a composite semiconductor structure, the method comprising:
- providing a substrate comprising a first semiconductor material;
- CVD-depositing an intermediate layer on a surface of the substrate, the intermediate layer comprising a glass material having a composition whereby, when subjected to a suitable heat treatment, the material undergoes a structural transformation becoming spongy;
- and
- applying a suitable heat treatment at a temperature in the range from 900° C. to 1200° C. to the substrate and as-deposited intermediate layer so that the intermediate layer becomes spongy consequent to the structural transformation,
- wherein the glass material comprises silicon oxide doped with phosphorous or silicon oxide doped with phosphorous and boron, and
- wherein the spongy transformation comprises the formation of microbubbles or microcavities containing a gaseous phase.
Dependencies are inferred from the claim text.