Selective epitaxy process control

摘要

Methods of selectively and epitaxially forming a silicon-containing material on a substrate surface contained within a process chamber are provided. In one or more embodiments, the pressure in the process chamber is reduced during deposition of material on the substrate and increased during etching of material from the substrate. According to an embodiment, process gases are flowed into the chamber through first zone and a second zone to provide a ratio of the amount of gas flowed to the first zone and the amount of gas flowed to the second zone. In one or more embodiments, the first zone is an inner radial zone and the second zone is an outer radial zone, and ratio of inner zone gas flow to outer zone gas flow is less during deposition than during etching. According to one or more embodiments, the selective epitaxial process includes repeating a cycle of a deposition and then an etching process, and an optional purge until the desired thickness of an epitaxial layer is grown.

主权项

1. A method of selectively and epitaxially forming a silicon containing material on a substrate surface comprising:
a) placing a substrate comprising a monocrystalline surface and at least a dielectric surface into a process chamber, the process chamber including a first radial zone and a second radial zone containing the substrate, each of said radial zones in separate fluid communication with a gas source for differentially controlling gas flow to the first radial zone and second radial zone of the substrate to provide a gas flow ratio of the first radial zone to the second radial zone, the first radial zone including an inner radial zone and the second radial zone including an outer radial zone; b) exposing the substrate to a gas consisting essentially of a deposition gas comprising a silicon-containing deposition gas and maintaining the pressure in the process chamber below about 50 Torr to form an epitaxial layer on the monocrystalline surface and a second material on the dielectric surface, the gas being flowed in a manner to provide a ratio of inner radial zone gas flow to outer radial zone gas flow (I/O) less than one; and c) subsequently stopping the flow of deposition gas to the process chamber, increasing the pressure in the process chamber and exposing the substrate to an etchant gas to maintain a relatively high etchant gas partial pressure and to etch the second material, the etchant gas flowed in a manner to provide an I/O greater than one; d) subsequently stopping the flow of etchant gas to the process chamber and flowing a purge gas into the process chamber; and e) sequentially repeating steps b), c) and d) at least once.