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Title: Apparatus for externally controlled closed-loop feedback digital epitaxy

A method and apparatus for digital epitaxy. The apparatus includes a pulsed gas delivery assembly that supplies gaseous material to a substrate to form an adsorption layer of the gaseous material on the substrate. Structure is provided for measuring the isothermal desorption spectrum of the growth surface to monitor the active sites which are available for adsorption. The vacuum chamber housing the substrate facilitates evacuation of the gaseous material from the area adjacent the substrate following exposure. In use, digital epitaxy is achieved by exposing a substrate to a pulse of gaseous material to form an adsorption layer of the material on the substrate. The active sites on the substrate are monitored during the formation of the adsorption layer to determine if all the active sites have been filled. Once the active sites have been filled on the growth surface of the substrate, the pulse of gaseous material is terminated. The unreacted portion of the gas pulse is evacuated by continuous pumping. Subsequently, a second pulse is applied when availability of active sites is determined by studying the isothermal desorption spectrum. These steps are repeated until a thin film of sufficient thickness is produced.
 [1];  [1]
  1. (Knoxville, TN)
Issue Date:
OSTI Identifier:
Martin Marietta Energy Systems, Inc. (Oak Ridge, TN) ORNL
Patent Number(s):
US 5540783
Contract Number:
Research Org:
Country of Publication:
United States
apparatus; externally; controlled; closed-loop; feedback; digital; epitaxy; method; pulsed; gas; delivery; assembly; supplies; gaseous; material; substrate; form; adsorption; layer; structure; provided; measuring; isothermal; desorption; spectrum; growth; surface; monitor; active; sites; available; vacuum; chamber; housing; facilitates; evacuation; adjacent; following; exposure; achieved; exposing; pulse; monitored; formation; determine; filled; terminated; unreacted; portion; evacuated; continuous; pumping; subsequently; applied; availability; determined; studying; steps; repeated; film; sufficient; thickness; produced; adsorption layer; pulsed gas; chamber housing; continuous pumping; growth surface; sufficient thickness; active sites; vacuum chamber; gaseous material; gas delivery; substrate following; digital epitaxy; closed-loop feedback; gas pulse; supplies gaseous; thermal desorption; externally controlled; loop feedback; controlled closed-loop; delivery assembly; /118/