Patent ID: 6057214
Filing Date: 2000-05-02
Classification: H01L

Abstract:
A method of forming a silicon-on-insulator trench isolation structure within a bulk silicon substrate, the method comprising the steps of:providing a bulk silicon substrate;forming a blocking layer on the upper surface of the bulk silicon substrate having a pattern to define thereunder in said bulk silicon substrate an active silicon-on-insulator region, a further active region, and a trench region within the bulk silicon substrate, the trench region positioned between the active silicon-on-insulator region and the further active region, the ability of the blocking layer to transmit selected ions capable of forming an insulator with silicon therethrough being less over the further active region than over the active silicon-on-insulator region;etching portions of the bulk silicon substrate to form the trench region between said further active region and said active silicon-on-insulator region;then implanting said selected ions capable of forming an insulator with silicon into the blocking layer at an energy level such that said ions either only pass through the portion of said blocking layer having greater ability to transmit said selected ions therethrough or pass through said the portion of said blocking layer having greater ability to transmit said selected ion therethrough to a greater depth in said bulk silicon substrate than through the portion of said blocking layer disposed over said further active area to form a buried insulator layer at a desired location and at a desired depth below the upper surface of the bulk silicon substrate in said active silicon-on-insulator region;removing the blocking layer; andannealing the structure, including the bulk silicon substrate, to form the silicon-on insulator trench isolation structure.