Capping technique for zone-melting recrystallization of insulated semiconductor films

• Main Authors: TSAUR; BOR-YEU, CHEN; CHENSON K
• Format: Patent
• Language: English
• Published: 26.12.1989
• Subjects: AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUSPOLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR; BASIC ELECTRIC ELEMENTS; CHEMISTRY; CRYSTAL GROWTH; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; METALLURGY; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; REFINING BY ZONE-MELTING OF MATERIAL; SEMICONDUCTOR DEVICES; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; SINGLE-CRYSTAL-GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL ORUNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL

Wetting of encapsulated silicon-on-insulator (SOI) films during a zone-melting recrystallization (ZMR) process is enhanced by a high temperature anneal of the SOI structure in a reactive nitrogen-containing ambient to introduce nitrogen atoms to the polysilicon/silicon dioxide cap interface. The technique is not only more effective in preventing cap fracture and enhancing crystal quality but it also susceptible to batch processing with noncritical parameters in a highly efficient, uniform manner. Preferably, the cap is exposed to 100% ammonia at 1100 DEG C. for one to three hours followed by a pure oxygen purge for twenty minutes. The ammonia atmosphere is reintroduced at the same temperature for another one to three hour period before ZMR. The process is believed to result in less than a half monolayer of nitrogen at the interior cap interface thereby significantly lowering the contact angle and improving the wetting character of the SOI structure.