Patent ID: 7208754
Filing Date: 2007-04-24
Classification: H01L

Abstract:
1. A semiconductor device, comprising: a substrate; a first epitaxial layer formed on the substrate, the first layer having lattice mismatch relative to the substrate; a second epitaxial layer formed on the first layer, the second layer having lattice mismatch relative to the first layer; a third epitaxial layer formed on the second layer, the third layer having lattice mismatch relative to the second layer; a first trench extending through the first layer, the first trench having first trench sidewalls; a second trench extending through the third layer and at least partially through the second layer, at least part of the second trench being aligned with at least part of the first trench, the second trench being at least partially filled with an insulating material, the second trench having second trench sidewalls, and at least one of the second trench sidewalls not being aligned with at least one of the first trench sidewalls.