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US 6,576,535 B2Granted
Carbon doped epitaxial layer for high speed CB-CMOS
AssigneeTexas Instruments Incorporated
InventorsVladimir F. Drobny, Dennis D. Liu
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AssigneeTexas Instruments Incorporated
InventorsVladimir F. Drobny, Dennis D. Liu
Estimating the term…
A method for fabricating a high speed complementary bipolar/CMOS device is disclosed which enables the forming of a silicon epitaxial layer in a PNP transistor having carbon incorporated therein to suppress boron up-diffusion from lower heavily boron-doped buried layers into upper PNP structures. According to an embodiment of the invention, an epitaxial layer is formed on a P type silicon substrate in which a plurality of P+ buried layer regions, a plurality of N+ buried layer regions, and a P+ field layer region occupying most of the substrate surface are diffused. The substrate is loaded in a reactor with a carrier gas and pre-baked at a temperature of approximately 850° C. for a time. The temperature is then increased to approximately 1050° C. and subjected to a high temperature bake cycle. A thin carbon-doped epitaxial cap layer is deposited on the substrate, which then is subjected to a high temperature gas purge cycle at approximately 1080° C. Then an N− epitaxial layer is deposited on the carbon-doped epitaxial cap layer at 1080° C. Use of a carbon-doped epitaxial cap layer significantly impedes boron up-diffusion from the lower buried layers into the upper PNP structures.
A method of making an epitaxial layer on a p type silicon substrate having in a major surface thereof a P+ field layer region in a substantial portion of the major surface, comprising:
A method of making an epitaxial layer on a silicon substrate having in a major surface thereof a P+ field layer region in a substantial portion of the major surface, comprising:
A method of making an epitaxial layer on a p-type substrate having in a major surface thereof a P+ field layer region in a substantial portion of the major surface, comprising:
A method of making an epitaxial layer on a substrate having in a major surface thereof a P+ field layer region in a substantial portion of the major surface, comprising:
A method of suppressing boron diffusion from a P+ buried layer to an N− epitaxial layer in a p-type CB-CMOS silicon substrate, the method comprising depositing a carbon-doped epitaxial layer between the p-type silicon substrate and the N− epitaxial layer.
A method of suppressing boron diffusion from a P+ buried layer to an N− epitaxial layer in a CB-CMOS silicon substrate, the method comprising depositing a carbon-doped epitaxial layer between the silicon substrate and the N− epitaxial layer;
Dependencies are inferred from the claim text.