Process for simultaneously gettering,passivating and locating a junction within a silicon crystal

Abstract

Abstract D R A W I N G AN EPITAXIAL LAYER IS DEPOSITED ONTO A SILICON CRYSTAL WITH THE LAYER AND ADJACENT CRYSTAL SURFACE BEING OF OPPOSITE CONDUCTIVITY TYPES AND THE EPITAXIAL LAYER CONTAINING A HIGHER IMPURITY CONCENTRATION. THE ADJACENT CRYSTAL SURFACE IS THEN CONVERTED TO THE CONDUCTIVITY TYPE OF THE EPITAXIAL LAYER TO DISPLACE THE JUNCTION INTO THE CRYSTAL AWAY FROM THE EPITAXIAL LAYER. SILICON DIOXIDE IS FORMED ON THE EXTERIOR SURFACES OF THE CRYSTAL TO ACT AS A PASSIVATION LAYER. BOTH STEPS ARE PERFORMED CONCURRENTLY BY HEATING THE CRYSTAL IN AN OXIDIZING ATMOSPHERE. A STRESSED REGION MAY BE FORMED ON THE CRYSTAL PRIOR TO HEATING THAT WILL TRAP FAST DIFFUSING IMPURITY ATOMS DURING HEATING. IN ONE FORM THE SILICON CRYSTAL IS GROOVED SO THAT THE GROOVED SURFACES INTERSECT THE FINAL LOCATION OF THE JUNCTION, AND THE CRYSTAL IS SUB-DIVIDED ALONG GROOVE TROUGH AREAS TO FORM SEPARATELY USEABLE, DISCRETE ELEMENTS.

Inventors

• 👤 Edwin J Mets

Bibliographic Details