Patent ID: 8796157

Claim:
A method of selective etching comprising: providing a substrate comprising a surface layer formed by first material and an intermediate layer formed by a second layer, said intermediate layer immediately adjacent to said surface layer and between said substrate and said surface layer, said first material comprising at least two different chemical elements and having semiconducting properties based on said at least two different chemical elements, and said second material being strained silicon; and providing strained silicon as a second material selected; and selectively etching said first material with a selectivity of at least 15:1 towards said second material by a liquid etchant flowing across and directly contacting the substrate surface layer at a flow sufficiently fast to generate a mean velocity v parallel to the substrate's surface layer of at least 0.1 m/s, wherein said substrate is rotated while exposed to said liquid etchant, wherein said liquid is dispensed onto the surface layer of the substrate in a continuous flow as a free beam having a defined axis such that the liquid contacts the substrate's surface at a point of impact defined as an intersection of the axis of the free beam and the substrate's surface, and the liquid is spread over the substrate's surface layer from said point of impact, wherein said point of impact of the liquid stream is moved across the surface layer of the substrate in a time sequence so as to provide uniform etching, wherein said liquid is dispensed at a volume flow from 0.05 l/min to 0.5 l/min.