Method and apparatus for monitoring surface layer growth
AssigneeThe Secretary of State for Defence in Her Britannic Majesty's Government for the United Kingdom of Great Britain and Northern Ireland
InventorDavid J. Robbins
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Abstract
A method of monitoring surface layer growth using light scattered off a surface illuminated e.g. by a laser. A small area of a surface of a substrate is illuminated and the light scattered in a non-specular direction is detected during cleaning and subsequent layer growth. The amount of light scattered varies strongly with surface characteristics and gives clear indication of the end of oxide removal, initiation of nucleation and quality of growing layers. The monitoring is used during e.g. chemical vapor deposition, or e.g. molecular beam epitaxy growth processes.
Claims23
A method of monitoring surface conditions on a surface of a subtrate being processed including the steps of:
- directing a beam of light onto at least one portion of an area of the surface being monitored;
- detecting light scattered from said at least one portion of an area in at least one non-specular reflection direction;
- changing the process parameters in response to detected changes on said at least one portion of said area of said surface.
Apparatus for monitoring surface conditions of a substrate including:
- means for cleaning or otherwise preparing a surface of the substrate;
- means for depositing a layer of material on the cleaned surface;
- means for directing light onto at least one portion of an area of the surface;
- means for detecting light scattered from said at least one portion of an area in at least one non-sspecular reflection direction;
- and
- means for changing one of cleaning and layer growth parameters in response to detected changes of scattered light.
Dependencies are inferred from the claim text.