SGT superjunction MOSFET structure
First Claim
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1. A metal-oxide-semiconductor field-effect transistor (MOSFET) device, comprising:
- a drift region of a first conductivity type provided on top of a heavily doped substrate of a same conductivity type;
a body region of a second conductivity type that is opposite to the first conductivity type provided above the drift region;
a plurality of trenches provided in the body region and extending into the drift region;
a heavily doped source region of the first conductivity type provided in the body region; and
a superjunction structure provided in the drift region including alternating first doped columns of the first conductivity type and second doped columns of the second conductivity type arranged in parallel, wherein each of the second doped columns is provided between two adjacent trenches, wherein each of the first doped columns has an extra charge density region near and adjacent to a corresponding one of the plurality of trenches, wherein the alternating first doped columns and the second doped columns are in substantial charge balance in the drift region.
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Abstract
A trench metal-oxide-semiconductor field-effect transistor (MOSFET) device includes a combination of shielded trench gate structure and a superjunction structure within an epitaxial layer including alternating n-doped and p-doped columns in an a drift region. In one example the gate trenches are formed in and over n-doped columns that have an extra charge region near and adjacent to the lower portion of the corresponding gate trench. The extra charge is balanced due to the shield electrodes in the gate trenches.
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Citations
25 Claims
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1. A metal-oxide-semiconductor field-effect transistor (MOSFET) device, comprising:
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a drift region of a first conductivity type provided on top of a heavily doped substrate of a same conductivity type; a body region of a second conductivity type that is opposite to the first conductivity type provided above the drift region; a plurality of trenches provided in the body region and extending into the drift region; a heavily doped source region of the first conductivity type provided in the body region; and a superjunction structure provided in the drift region including alternating first doped columns of the first conductivity type and second doped columns of the second conductivity type arranged in parallel, wherein each of the second doped columns is provided between two adjacent trenches, wherein each of the first doped columns has an extra charge density region near and adjacent to a corresponding one of the plurality of trenches, wherein the alternating first doped columns and the second doped columns are in substantial charge balance in the drift region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A metal-oxide-semiconductor field-effect transistor (MOSFET) device, comprising:
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a drift region of the a conductivity type provided on top of a heavily doped layer of a same conductivity type; a body region of a second conductivity type that is opposite to the first conductivity type provided above the drift region; a plurality of trenches provided in the body region and extending into the drift region; a heavily doped source region of the first conductivity type provided in the body region; and a superjunction structure provided in the drift region including alternating first doped columns of the first conductivity type and second doped columns of the second conductivity type arranged in parallel, wherein each of the second doped columns is provided between two adjacent trenches, wherein each of the first doped columns and the second doped columns extends below a bottom of the trenches, wherein the alternating first doped columns and the second doped columns are in substantial charge balance in the drift region. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A superjunction semiconductor device, comprising:
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a drift region of a first conductivity type provided on top of a heavily doped layer of a same conductivity type; a body region of a second conductivity type that is opposite to the first conductivity type provided above the drift region; and a superjunction structure provided in the drift region including alternating first doped columns of the first conductivity type and second doped columns of the second conductivity type arranged in parallel, wherein the first doped columns have a varying doping profile across the drift region, wherein a middle region above a bottom region and below an upper region has a net charge density lower than a net charge density in the bottom region and the upper region, wherein the alternating first doped columns and the second doped columns are in substantial charge balance in the drift region. - View Dependent Claims (20, 21, 22, 23, 24)
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25. A superjunction semiconductor device, comprising:
a drift region comprising a superjunction structure provided in the drift region including alternating first doped columns of a first conductivity type and second doped columns of the second conductivity type arranged in parallel, wherein the first doped columns comprising a plurality of epitaxial layers doped with the first conductivity having a varying doping profile across the drift region, wherein a middle region above a bottom region and below an upper region has a dose for each epitaxial layer lower than a dose in each of epitaxial layer in the bottom region and in the upper region, wherein the alternating first doped columns and the second doped columns are in substantial charge balance in the drift region.
Specification