Abstract: An isolation method for a highly-integrated semiconductor device includes growing an epitaxial layer on the entire surface of a semiconductor substrate including over a trench on which an oxide layer is formed, thereby leaving the inside of the trench empty. A portion of the epitaxial layer which is located over the trench is then oxidized to form an isolation region.

Abstract: A trench isolated integrated circuit includes at least one void in the trench at the trench corner. The trench comprises a trench wall, a trench floor and a trench corner between the trench wall and the trench floor. An insulating region is included in the trench, including on the trench floor and on the trench wall. The insulating region is spaced apart from the trench corner to define a void at the trench corner. The insulating region may also be spaced apart from a portion of the trench wall, to define a second void on the trench wall that is spaced apart from the void at the trench corner. The voids may reduce stresses cased by the thermal mismatch between the insulating region and the integrated circuit substrate, to thereby improve integrated circuit reliability and/or performance. Methods of forming trench isolated integrated circuits according to invention include the steps of forming a trench in an integrated circuit substrate.