Apparatus and process for growing silicon epitaxial layer
AssigneeSEH America, Inc.
InventorTodd A. Hamilton
Life of this patent
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Abstract
An apparatus and a process for growing a silicon epitaxial layer on a main surface of a silicon substrate wafer are disclosed. The apparatus and process provide a reactor and a gas feeder system. The gas feeder system utilizes an auxiliary dopant supply mass flow control (MFC) to provide an auxiliary dopant only into a central injector that effects epitaxial deposition on the center of the wafer for autodoping correction. An auxiliary bellows metering valve is provided between the auxiliary MFC and the center injector to absorb pressure variations in the central flow line to prevent the pressure variations from reaching the auxiliary MFC. This results in a stable and consistent dopant concentration and resistivity profile.
Claims8
A process for growing a silicon epitaxial layer on a main surface of a silicon wafer which is held in a horizontal type of chamber, said silicon wafer having a center portion and peripheral portions, the process comprising the steps of:
- concurrently feeding parallel flows of reactive gas from a plurality of positions which are arranged in a width direction of the flows into the chamber so that an epitaxial layer is formed in the vicinity of the center of the silicon wafer and in the vicinity of the peripheral portions of the wafer, the reactive gas comprising a silicon source, a dopant and hydrogen;
- absorbing pressure variations in the flow of reactive gas toward the center of the silicon wafer;
- and
- adjusting the concentration of the dopant in the reactive gas which is fed toward the center portion of the silicon wafer so that the resistivity of the epitaxial layer formed in the vicinity of the center of the silicon wafer is approximately the same as that of the vicinity of the peripheral portions thereof.
A process for growing a silicon epitaxial layer on a main surface of a silicon wafer which is held in a horizontal type of chamber, wherein said silicon wafer has a center portion and peripheral portions, the process comprising the steps of:
- concurrently feeding parallel flows of reactive gas from a plurality of positions which are arranged in a width direction of the flows into the chamber so that an epitaxial layer is formed in the vicinity of the center of the silicon wafer and in the vicinity of the peripheral portions of the wafer, the reactive gas comprising a silicon source, a dopant and hydrogen;
- feeding a predetermined amount of auxiliary dopant into flows of the reactive gas which is fed toward the center portion of the silicon wafer at a constant concentration so that the resistivity of the epitaxial layer formed in the vicinity of the center of the silicon wafer is approximately the same as that of the vicinity of the peripheral portions thereof;
- and
- absorbing pressure variations in the flow of reactive gas toward the center of the silicon wafer.
Dependencies are inferred from the claim text.