Subnanometer scale characterization of III-V-heterostructures

Heterostructures based on III-V semiconductors play a dominant role for the production of optoelectronic and electronic high-speed or high-frequency devices. The necessary band-gap engineering is achieved by optimized growth procedures which allow to change the chemical composition and the crystal structure (e.g. strain or ordering) on the subnanometer scale. The evaluation of individual heterointerfaces with respect to chemical composition and crystal structure requires characterization techniques which offer the necessary high spatial resolution. Scanning transmission electron microscopy (STEM) offers several such quantitative techniques. It is the intention of this paper to demonstrate the capabilities of STEM in the subnanometer characterization of III-V-heterostructures based on InP-substrates. Additionally, the data obtained from nanocharacterization can be correlated to device performance.