Optical control of growth of AlxGa1−xAs by organometallic molecular beam epitaxy

Using spectroellipsometry, we obtain information on the near-surface composition x of epitaxial AlxGa1−xAs layers during crystal growth by organometallic molecular beam epitaxy and use this information to regulate the flow of triethylaluminum to the growth surface. The resulting closed-loop control system maintains the imaginary part of the dielectric response of thick AlxGa1−xAs films constant to an equivalent compositional precision better than ±0.001 over extended periods of time.