Chemical vapor deposition of thick deposits of isotropic boron nitride

Abstract

Abstract SUBSTRATE MEMBER IS HEATED TO A SUITABLE TEMPERATURE IN EXCESS OF 1200*C. IN A DEPOSITION CHAMBER PARTIALLY EVACUATED TO SUBATMOSPHERIC PRESSURE. DIBORANE GAS IS REACTED WITH AMMONIA GAS WITH A TEMPERATURE RANGE OF 200-300*C. TO PRODUCE AN INTERMEDIATE GASEOUS REACTION PRODUCT. THE INTERMEDIATE GASEOUS REACTION PRODUCT IS CAUSED TO FLOW ACROSS THE HEATED SUBSTRATE TO CAUSE DECOMPOSITION OF THE GASEOUS REACTION PRODUCT WITH RESULTANT DEPOSITION OF A RELATIVELY THICK DEPOSIT OF ISOTROPIC BORON NITRIDE ONTO THE HEATED SUBSTRATE. IN A PREFERRED EMBODIMENT, THE SUBSTRATE MEMBER IS TUBULAR AND COAXIALLY ALIGNED WITH A GASEOUS STREAM OF THE INTERMEDIATE GASEOUS REACTION PRODUCT SUCH THAT THE GASEOUS STREAM FLOWS THROUGH THE INTERIOR OF THE TUBULAR SUBSTRATE FOR DEPOSITING THE BORON NITRIDE ON THE INTERIOR SURFACES OF THE TUBULAR SUBSTRATE. THE DIBORANE GAS IS INTRODUCED IN A RELATIVELY INERT CARRIER GAS STREAM IN A CONCENTRATION OF MORE THAN 50,000 PARTS PER MILLION DIBORANE GAS. THE SUBATMOSPHERIC PRESSURE WITHIN THE DEPOSITION CHAMBER IS PREFERABLY LESS THAN 3/10 OF AN ATMOSPHERE SUCH THAT THE CONCENTRATION OF THE INTERMEDIATE GASEOUS REACTION PRODUCT IS RELATIVELY HIGH AND THE PROBABILITY THAT THE REACTION PRODUCT WILL REACH THE INTERIOR WALL OF THE SUBSTRATE IS RELATIVELY HIGH TO FACILITATE RELATIVELY RAPID GROWTH RATES OF THE BORON NITRIDE AND EFFICIENT UTILIZATION OF THE INTERMEDIATE GASEOUS REACTION PRODUCT.

Inventors

• 👤 Malcolm L Kinter
• 👤 Ira Weissman

Bibliographic Details