Process for forming an interface between silicon carbide and silicon oxide with low density of states
AssigneeSTMicroelectronics S.r.l.
InventorsGiovanni Abagnale, Dario Salinas, Sebastiano Ravesi
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Abstract
An embodiment of a process for forming an interface between a silicon carbide (SiC) layer and a silicon oxide (SiO2) layer of a structure designed to conduct current is disclosed. A first epitaxial layer having a first doping level is homo-epitaxially grown on a substrate. The homo-epitaxial growth is preceded by growing, on the first epitaxial layer, a second epitaxial layer having a second doping level higher than the first doping level. Finally, the second epitaxial layer is oxidized so as to be totally removed. Thereby, a silicon oxide layer of high quality is formed, and the interface between the second epitaxial layer and silicon oxide has a low trap density.
Claims29
A method for forming an interface between a silicon carbide layer and a silicon oxide layer of a structure designed to conduct current, said method comprising:
- homo-epitaxially growing a first epitaxial layer having a first doping level;
- homo-epitaxially growing, on said first epitaxial layer, a second epitaxial layer having a second doping level higher than said first doping level;
- and
- oxidizing said second epitaxial layer and forming a silicon oxide layer that comprises a layer interface between the first epitaxial layer and the silicon oxide layer.
A method for forming an interface between a silicon carbide layer and a silicon oxide layer of a structure designed to conduct current, said method comprising:
- homo-epitaxially growing a first epitaxial layer having a first doping level;
- homo-epitaxially growing, on said first epitaxial layer, a second epitaxial layer having a second doping level higher than said first doping level;
- and
- oxidizing said second epitaxial layer and forming a silicon oxide layer;
- wherein said step of homo-epitaxial growing a second epitaxial layer comprises:
- prior to said step of homo-epitaxial growing a first epitaxial layer, providing a substrate of silicon carbide having a third doping level higher than said first doping level;
- homo-epitaxially growing, on said substrate, a buffer layer having said third doping level;
- and
- introducing, in said second epitaxial layer, a flow of dopants such as to cause said second doping level of said second epitaxial layer to become higher than or equal to said third doping level of said substrate and of said buffer layer.
A method for forming an interface between a silicon carbide layer and a silicon oxide layer of a structure designed to conduct current, said method comprising:
- homo-epitaxially growing a first epitaxial layer having a first doping level;
- homo-epitaxially growing, on said first epitaxial layer, a second epitaxial layer having a second doping level higher than said first doping level;
- and
- oxidizing said second epitaxial layer and forming a silicon oxide layer;
- wherein said step of oxidizing said second epitaxial layer and forming a silicon oxide layer comprises modulating the duration of said step of oxidizing so as to entirely consume said second epitaxial layer.
A method for fabricating a semiconductor structure, comprising:
- epitaxially growing a first silicon-carbide layer having a first doping level;
- epitaxially growing a second silicon-carbide layer on the first silicon-carbide layer, the second silicon-carbide layer having a second doping level different than that of the first doping level;
- and
- oxidizing the second silicon-carbide layer to form a silicon dioxide layer that replaces the second silicon-carbide layer.
A method for fabricating a semiconductor structure, comprising:
- epitaxially growing a first silicon-carbide layer having a first doping level;
- epitaxially growing a second silicon-carbide layer on the first silicon-carbide layer, the second silicon-carbide layer having a second doping level different than that of the first doping level;
- and
- oxidizing the second silicon-carbide layer to form a silicon dioxide layer;
- wherein epitaxially growing a first silicon-carbide layer having a first doping level comprises epitaxially growing the first silicon-carbide layer on a silicon carbide buffer layer;
- and
- wherein the silicon carbide buffer layer has a third doping level that is greater than that of the first doping level and less than that of the second doping level.
A method for fabricating a semiconductor structure, comprising:
- epitaxially growing a first silicon-carbide layer having a first doping level;
- epitaxially growing a second silicon-carbide layer on the first silicon-carbide layer, the second silicon-carbide layer having a second doping level different than that of the first doping level;
- and
- oxidizing the second silicon-carbide layer to form a silicon dioxide layer;
- wherein oxidizing the second silicon-carbide layer to form a silicon dioxide layer comprises oxidizing substantially all of and substantially only the second silicon-carbide layer.
A method for fabricating a semiconductor structure, comprising:
- epitaxially growing a first silicon-carbide layer having a first doping level;
- epitaxially growing a second silicon-carbide layer on the first silicon-carbide layer, the second silicon-carbide layer having a second doping level different than that of the first doping level;
- and
- oxidizing the second silicon-carbide layer to form a silicon dioxide layer;
- wherein oxidizing the second silicon-carbide layer to form a silicon dioxide layer comprises oxidizing the second silicon-carbide layer to form an interface between the silicon dioxide layer and the first silicon-carbide layer.
Dependencies are inferred from the claim text.