Optical control of deposition of crystal monolayers
AssigneeBell Communications Research, Inc.
InventorsDavid E. Aspnes, Rajaram Bhat, Etienne G. Colas, Leigh T. Florez, James P. Harbison, Amabrose A. Studna
Life of this patent
Estimating the term…
Abstract
A method and apparatus for epitaxial growth of precisely one monolayer. The growth is by organometallic chemical vapor deposition in which the substrate is alternately exposed to the anion and cation of a III-V compound. During deposition of the cation, for instance Ga or Al, reflectance difference spectroscopy is performed to obtain the difference of reflected light beams polarized in orthogonal directions. A growth of a monolayer and even of a partial monolayer can be monitored in real time.
Claims19
A crystal growing apparatus comprising:
- means for depositing atoms upon a surface of a substrate;
- and
- optical monitoring means, operable during an operation of said depositing means, for monitoring said atoms deposited upon said surface, said optical monitoring means comprising a source of light irradiated upon said substrate and interacting with said deposited atoms, polarization detecting means for detecting respective quantities of two polarization components of a beam of light resultant from said irradiated light having interacted with said deposited atoms and differencing means for comparing said respective quantities.
A method of growing a crystal, comprising the steps of:
- depositing atoms upon a surface of a substrate;
- irradiating said substrate with light during said depositing step and causing said irradiated light to reflect resultant light in a first direction;
- detecting in said first direction two respective quantities of orthogonal polarization components of said resultant light;
- differencing said two quantities to produce an output representative of an amount of said atoms deposited upon said surface;
- and
- controlling said depositing step in response to said output of said differencing step.
Dependencies are inferred from the claim text.