Quick Turnaround Technique for Highlighting Defects in Thin Si/SiGe Bilayers

A chemical defect etching technique is described that permits accurate determination of defect density in thin Si/SiGe bilayer films. The etching technique is capable of distinguishing between isolated defect pits, such as threading defects, and planar defects in the top Si layer within the resolution of optical microscopy. A strained Si layer grown on a silicon-germanium-on-insulator substrate with a 40 atom % Ge content was analyzed using the new etching technique and the measured defect density compared well with plan-view transmission electron microscopy (PV-TEM) and cross-sectional TEM (X-TEM) results. X-TEM revealed that the planar defects observed in the defect etching images correspond to microtwin defects. (C) 2004 The Electrochemical Society.