Ion-free insulating layers

Abstract

Abstract ION CONTAMINATION OF INSULATORS, SUCH AS THERMALLY GROWN SILICON DIOXIDE LAYERS ON SILICON WAFERS IS VIRTUALLY ELIMINATED, IF, AFTER OXIDE GROWTH, THE WAFERS ARE COOLED IN AN ION-FREE ZONE. A CYLINDRICAL, INNER, QUARTZ SLEEVE, PREFERABLY BAFFLED, IS INTERPOSED BETWEEN THE REACTION TUBE AND A WAFER CONTAINING BOAT WHILE A PURGING GAS SUCH AS ARGON, NITROGEN, HELIUM AND OTHER INERT GASES IS DIRECTED INTO THE SLEEVE OVER THE OXIDIZED WAFERS TO PREVENT CONTAMINATION OF THE WAFER BY IONS OUT-GASSING FROM THE WALLS OF THE REACTION TUBE DURING THE COOLING CYCLE. ALTERNATIVELY, THE PORTION OF THE TUBE DESIGNATED FOR WAFTER COOLING IS CONTINUOUSLY BAKED BEFORE AND DURING THE OXIDE GROWTH PROCESS AND COOLED SIMULTANEOUSLY WITH THE WAFERS THEREBY PRVENTING THE BUILDUP OF IONS ON THE WALLS IN THE WATER COOLING PORTION OF THE TUBE. ALTERNATIVELY, A QUARTZ SLEEVE IS INTERPOSED BETWEEN THE WAFER BOAT AND REACTION TUBE AND EXTENDS FROM THE HOT ZONE AND THROUGH THE PORTION OF THE TUBE DESIGNATED FOR WAFTER COOLING. THE INNER SLEEVE IS REMOVED FOR WAFER COOLING.

Inventors

• 👤 James L Reuter
• 👤 Jagtar S Sandhu

Bibliographic Details