High acceptor level doping in silicon germanium
AssigneeInternational Business Machines Corporation
InventorsMona Abdulkhaleg Ebrish, Oleg Gluschenkov, Shogo Mochizuki, Alexander Reznicek
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Abstract
A gallium-doped sacrificial epitaxial or polycrystalline germanium layer is formed on a silicon germanium substrate having a high percentage of germanium followed by annealing to diffuse the gallium into the silicon germanium substrate. The germanium layer is selectively removed to expose the surface of a gallium-doped silicon germanium region within the silicon germanium substrate. The process has application to the formation of electrically conductive regions within integrated circuits such as source/drain regions and junctions without the introduction of carbon into such regions.
Claims12
A method for providing gallium doping in a silicon germanium layer, comprising:
- obtaining a substrate including a silicon germanium alloy surface layer having the composition Si1-xGex where x is 0.85 or greater;
- forming a gallium-doped germanium layer on the silicon germanium alloy surface layer, the germanium layer having a higher germanium content and a lower melting point than the silicon germanium alloy surface layer;
- causing diffusion of gallium from the germanium layer into the silicon germanium alloy surface layer, thereby forming a gallium-doped silicon germanium region within the silicon germanium alloy surface layer, and
- removing the germanium layer from the silicon germanium alloy surface layer.
Dependencies are inferred from the claim text.