Transmission electron microscopy of heteroepitaxial layer structures

• Published in: Applied surface science Vol. 50; no. 1; pp. 19 - 27
• Main Author: Cerva, H.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.1991; Elsevier Science
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Physics; Solid surfaces and solid-solid interfaces; Surface and interface dynamics and vibrations; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/0169-4332(91)90134-6

The characterization of heterostructural layers by transmission electron microscopy using cleaved wedge specimens proves to be a fast analysis method. Examples are given for GaAlAs/GaAs and strained GaInAs/GaAs layer systems. It is demonstrated that the (200) dark-field contrast of GaInAs/GaAs layers reverses at an In concentration of x ≈ 0.47. Experimental high-resolution electron images of the edges of cleaved 90° wedges compare very well with computer-simulated images. Characteristic image features in GaAs and AlAs are explained by non-linear beam interactions and are shown to be sensitive to electron beam misalignment. These investigations are important to make a more precise assessment of interfaces possible.