Method for producing a freestanding and stress-free epitaxial layer starting from a disposable substrate patterened in etched pillar array

Abstract

The method provides for the growth of an epitaxial layer () made of a first semiconductor material on a substrate () made of a second semiconductor material; the materials are different and have different CTEs; the method comprises the steps of: A) patterning the substrate () by an etching process so to form an array of pillars (), the pillars () being laterally spaced from each other and having a top section () larger than a bottom section () and/or intermediate sections (), B) depositing the second semiconductor material on top of the pillars () at a growth temperature so to form an epitaxial layer () generated by vertical and lateral growth, and C) inducing breaking of the pillars () by cooling the substrate () and the epitaxial layer () below the growth temperature.