Product Specifications : kSA ICE for MBE
• Growth Rate
k-Space Associates, Inc. offers the kSA Integrated Control for Epitaxy (kSA ICE) instrument for MBE systems. The kSA ICE instrument is a modular in situ metrology system that has mainly been used in MOCVD systems to date. However, with optics customized to accommodate the longer optical path lengths and large substrate wobble often found in MBE systems, this tool is capable of performing continuous reflectivity measurements at a working distance of up to 1m. Although the substrate wobble introduces a considerable amount of variation in the reflectivity signals, kSA ICE is capable of producing excellent results due to its combination of high sensitivity, optimized collection optics, and a very robust reflectivity-fitting algorithm. Note that kSA ICE measurements can also be synchronized with the substrate rotation to remove the wobble-induced noise in the reflectivity measurement.
The figure on the upper right shows laser-based 974 nm reflectivity data from AlAsSb and GaSb films continuously acquired during rotation in a MBE tool. The scatter seen in the data results from the presence of substrate wobble in this MBE tool. Despite the significant wobble, the kSA ICE tool is able to fit the oscillations and provide a growth rate for both layers. The figure on the lower right shows a “close-up” view of the wobble induced data scatter. The kSA ICE algorithm achieves a growth rate fit after a layer thickness of ~ λ/4n. In the case of a GaSb layer (n=4.25) measured with 974 nm light, we are able to acquire a fit after 60 nm, and after 75 nm of deposition the fit is fully converged. The ability for a reflectivity based tool to determine a given layer thickness depends on the material layer properties and the wavelength of the laser or LED used for measurement. Let k-Space help configure a kSA ICE tool for your MBE deposition application.
kSA ICE for MBE Models
Reflectivity-based measurement tools require the use of an angled viewport to minimize back reflections and to provide the greatest dynamic range for your measurement. Laser upgrade options are available, as are reflectivity-only ICE MBE tools. Contact your k-Space representative for further details.
The drawings above show two standard ICE for MBE models. The first model (left) is used for emissivity correcting pyrometry and 940 nm reflectivity. The second (right) adds the ability to measure 532 nm reflectivity in addition to the standard 960 nm temperature and reflectivity measurement. Custom LED-based and laser-based configurations available upon request.
k-Space has an expansive network of distributors to best serve our worldwide customer base.