Method of preventing surface roughening during hydrogen prebake of SiGe substrates
First Claim
1. A method of forming an epitaxial silicon-containing layer on a silicon germanium surface, said method comprising:
- performing an ex-situ chemical oxide removal process on said silicon germanium surface so as to partially remove oxygen from said silicon germanium surface and leave a first amount of oxygen on said silicon germanium surface;
heating said silicon germanium surface sufficiently to remove additional oxygen from said silicon germanium surface and leave a second amount of oxygen, less than said first amount, on said silicon germanium surface; and
epitaxially growing said epitaxial silicon-containing layer on said silicon germanium surface.
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Abstract
The invention forms an epitaxial silicon-containing layer on a silicon germanium, patterned strained silicon, or patterned thin silicon-on-insulator surface and avoids creating a rough surface upon which the epitaxial silicon-containing layer is grown. In order to avoid creating the rough surface, the invention first performs a hydrofluoric acid etching process on the silicon germanium, patterned strained silicon, or patterned thin silicon-on-insulator surface. This etching process removes most of oxide from the surface, and leaves a first amount of oxygen (typically 1×1013-1×1015/cm2 of oxygen) on the silicon germanium, patterned strained silicon, or patterned thin silicon-on-insulator surface. The invention then performs a hydrogen pre-bake process which heats the silicon germanium, patterned strained silicon, or patterned thin silicon-on-insulator surface sufficiently to remove additional oxygen from the surface and leave a second amount of oxygen, less than the first amount, on the silicon germanium, patterned strained silicon, or patterned thin silicon-on-insulator surface. The heating process leaves an amount of at least 5×1012/cm2 of oxygen (typically, between approximately 1×1013/cm2 and approximately 5×1013/cm2 of oxygen) on the silicon germanium, patterned strained silicon, or patterned thin silicon-on-insulator surface. By leaving a small amount of oxygen on the silicon germanium, patterned strained silicon, or patterned silicon-on-insulator surface, the heating processes avoid changing the roughness of the silicon germanium, patterned strained silicon, or patterned thin silicon-on-insulator surface. Then the process of epitaxially growing the epitaxial silicon-containing layer on the silicon germanium, patterned strained silicon, or patterned silicon-on-insulator surface is performed.
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Citations
20 Claims
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1. A method of forming an epitaxial silicon-containing layer on a silicon germanium surface, said method comprising:
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performing an ex-situ chemical oxide removal process on said silicon germanium surface so as to partially remove oxygen from said silicon germanium surface and leave a first amount of oxygen on said silicon germanium surface;
heating said silicon germanium surface sufficiently to remove additional oxygen from said silicon germanium surface and leave a second amount of oxygen, less than said first amount, on said silicon germanium surface; and
epitaxially growing said epitaxial silicon-containing layer on said silicon germanium surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of forming an epitaxial silicon-containing layer on a silicon surface, said method comprising:
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performing an ex-situ chemical oxide removal process on said silicon surface so as to partially remove oxygen from said silicon surface and leave a first amount of oxygen on said silicon surface;
heating said silicon surface sufficiently to remove additional oxygen from said silicon surface and leave a second amount of oxygen, less than said first amount, on said silicon surface; and
epitaxially growing said epitaxial silicon-containing layer on said silicon surface. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of forming an epitaxial silicon-containing layer on a silicon surface, wherein said silicon surface comprises one of a patterned strained silicon surface and a patterned thin silicon-on-insulator (SOI) surface, said method comprising:
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performing an ex-situ chemical oxide removal process on said silicon surface so as to partially remove oxygen from said silicon surface and leave a first amount of oxygen on said silicon surface;
heating said silicon surface sufficiently to remove additional oxygen from said silicon surface and leave a second amount of oxygen, less than said first amount, on said silicon surface; and
epitaxially growing said epitaxial silicon-containing layer on said silicon surface.
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Specification