Monolithically-integrated buck converter
AssigneeFairchild Semiconductor Corporation
InventorChristopher Kocon
Life of this patent
Estimating the term…
Abstract
An integrated buck converter is formed on a substrate of a first polarity type and having a first and second substrate surface. An epitaxial layer is formed over the first substrate surface and has a first epitaxial layer surface. A drift region lightly-doped with dopants of a second polarity type opposite the first polarity type is disposed within a first portion of the epitaxial layer. A high-side transistor is formed in the drift region. A low-side transistor is formed in a second portion of the epitaxial layer outside the drift region. A combined high-side source and low-side drain contact is disposed over the second substrate surface. Means for connecting the high-side source to the combined high-side source and low side drain contact are provided.
Claims42
In a common substrate with a top and a bottom surface, an integrated circuit comprising at first transistor with an input terminal on the top surface and first transistor output means for conducting current toward the bottom surface, a second transistor with an output terminal on the top surface and second transistor input means for conducting current toward the top surface from the bottom surface, and a conductive layer in the bottom surface for connecting the first transistor output means to the second transistor input means.
An integrated transistor module, comprising:
- a substrate of a first polarity type, said substrate having a first substrate surface and a second substrate surface opposite said first substrate surface;
- an epitaxial layer formed over said first substrate surface and having a first epitaxial layer surface;
- a drift region lightly doped with dopants of a second polarity type, said second polarity type opposite said first polarity type, said drift region being disposed within a first portion of said epitaxial layer;
- at least one high-side transistor associated with said drift region;
- at least one low-side transistor associated with a second portion of said epitaxial layer, said second portion not including said drift region;
- a combined high-side source and low-side drain contact disposed over said second substrate surface;
- and
- a high-side source current-carrying means for carrying a current flowing through said high-side source to said combined high-side source and low side drain contact.
An integrated circuit structure, comprising:
- a substrate of a first polarity type, said substrate having a first substrate surface and a second substrate surface opposite said first substrate surface;
- an epitaxial layer formed over said first substrate surface and having a first epitaxial layer surface;
- a drift region lightly doped with dopants of a second polarity type, said second polarity type opposite said first polarity type, said drift region being disposed within said epitaxial layer;
- at least one first transistor associated with said drift region, each said at least one first transistor having a first gate, first drain and first source;
- a first drain contact formed over at least a portion of said drift region;
- a first current-carrying means configured for carrying a current flowing through said first source to said second substrate surface;
- and
- a first source contact formed over said second substrate surface.
The integrated circuit structure of claim 29, wherein said second current-carrying means comprises:
- a second sinker trench extending through said epitaxial layer from said first epitaxial layer surface into and terminating within said substrate, said second sinker trench extending through said first drain;
- a layer of insulating material lining sidewalls of said sinker trench;
- conductive material disposed within said sinker trench;
- and
- a combined first source and second drain contact thereby being conjunctively formed by said first source contact and said second sinker trench.
An integrated buck converter, comprising:
- a substrate of a first polarity type, said substrate having a first substrate surface and a second substrate surface opposite said first substrate surface;
- an epitaxial layer formed over said first substrate surface and having a first epitaxial layer surface;
- a drift region lightly doped with dopants of a second polarity type, said second polarity type opposite said first polarity type, said drift region being disposed within a first portion of said epitaxial layer;
- at least one high-side transistor associated with said drift region;
- at least one low-side transistor associated with a second portion of said epitaxial layer, said second portion not including said drift region;
- a combined high-side source and low-side drain contact disposed over said second substrate surface;
- and
- means for connecting said high-side source to said combined high-side source and low side drain contact.
A method of forming an integrated transistor module, comprising:
- fabricating in a drift region of a semiconductor substrate at least one high-side MOSFET having a high-side gate, drain and source;
- fabricating in an epitaxial layer of the semiconductor substrate and outside of the drift region at least one low-side MOSFET having a low-side gate, drain and source;
- interconnecting the high-side source and low-side drain with the semiconductor substrate;
- and
- forming a combined high-side source and low-side drain contact on a surface of the semiconductor substrate opposite the high-side
Dependencies are inferred from the claim text.