Patent ID: 6524929
Filing Date: 2003-02-25
Classification: H01L

Abstract:
A method of isolation of active islands on a silicon-on-insulator semiconductor device, comprising the steps of:providing a silicon-on-insulator semiconductor wafer having a silicon active layer, a dielectric insulation layer and a silicon substrate, in which the silicon active layer is formed on the dielectric insulation layer and the dielectric insulation layer is formed on the silicon substrate; forming an isolation trench through the silicon active layer, the isolation trench defining at least one active island in the silicon active layer; depositing a passivating insulator in a lower portion of the isolation trench to a depth sufficient to provide a protective shield or barrier whereby a bird's beak cannot form between the silicon active layer and the dielectric insulation layer; rounding at least one corner of the active island in an upper portion of the silicon active layer and forming a sidewall oxide liner in the isolation trench by a thermal oxidation of the silicon active layer exposed in the isolation trench; and filling the isolation trench above the passivating insulator with a trench isolation material.