Isotopically pure silicon-on-insulator wafers and method of making same
The present invention provides improved semiconductor wafer structures having isotopically-enriched layers and methods of making the same.
1. A semiconductor wafer structure comprising:
an isotopically-enriched semiconductor material layer on a first surface of silicon nitride; and
a layer of semiconductor material having natural isotopic ratios on a second surface of said silicon nitride, said second surface opposite said first surface, wherein:
said isotopically-enriched semiconductor material layer has a higher thermal conductivity than said layer of semiconductor material having natural isotopic ratios.
2. The wafer structure of claim 1 , wherein the isotopically-enriched semiconductor material layer comprises a semiconductor material selected from the group consisting of isotopically-enriched silicon, isotopically-enriched germanium, silicon-germanium alloys and combinations and alloys thereof.
3. The semiconductor wafer structure of claim 1 , wherein the isotopically-enriched semiconductor comprises silicon enriched to at least 98% 28 Si.
4. The semiconductor wafer structure of claim 1 , wherein the isotopically-enriched semiconductor comprises geranium enriched to at least 85% 74 Ge.
5. The semiconductor wafer structure of claim 1 , wherein the isotopically-enriched semiconductor comprises geranium enriched to at least 80% of one of the germanium isotopes.