Insulated gate bipolar transistor with improved latch-up current level and safe operating area
First Claim
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1. A UMOS IGBT comprising:
- a body of semiconductor material having first and second opposed major surfaces;
said first major surface having a substantially planar plateau portion, a valley portion interspersed with said plateau portion and a pedestal wall portion connecting said plateau and valley portions, said pedestal wall portion and said plateau portion together bounding a pedestal portion of said body of semiconductor material;
a collector region of one type conductivity disposed adjacent said second major surface;
a drift region of opposite type conductivity disposed adjacent said collector region, forming a first PN junction therewith and extending to said valley portion of said first major surface;
a base region of said one type conductivity disposed in said pedestal portion of said body adjacent to said drift region, forming a second PN junction with said drift region and extending to said pedestal wall and plateau portions of said first major surface;
a source region of said opposite conductivity type, said source region being disposed in said pedestal portion of said body, forming a third PN junction with said base region and extending to said plateau and pedestal wall portions of said first major surface;
an insulated gate electrode disposed on said pedestal wall portion of said first major surface adjacent said base region and extending from said source region to said drift region for controlling the conductivity of a channel portion of said base region extending between said source and drift regions;
a collector electrode disposed on said second major surface in ohmic contact with said collector region;
a source electrode disposed on said plateau portion of said first major surface in ohmic contact with said base region and said source region; and
said base region comprising at least 40% of the area of said first major surface which is disposed in ohmic contact with said source electrode
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Abstract
A UMOS IGBT has a source electrode ohmic contact area which is at least 40% base region and preferably at least 50% base region in order to provide a high latching current and a large safe operating area.
46 Citations
29 Claims
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1. A UMOS IGBT comprising:
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a body of semiconductor material having first and second opposed major surfaces; said first major surface having a substantially planar plateau portion, a valley portion interspersed with said plateau portion and a pedestal wall portion connecting said plateau and valley portions, said pedestal wall portion and said plateau portion together bounding a pedestal portion of said body of semiconductor material; a collector region of one type conductivity disposed adjacent said second major surface; a drift region of opposite type conductivity disposed adjacent said collector region, forming a first PN junction therewith and extending to said valley portion of said first major surface; a base region of said one type conductivity disposed in said pedestal portion of said body adjacent to said drift region, forming a second PN junction with said drift region and extending to said pedestal wall and plateau portions of said first major surface; a source region of said opposite conductivity type, said source region being disposed in said pedestal portion of said body, forming a third PN junction with said base region and extending to said plateau and pedestal wall portions of said first major surface; an insulated gate electrode disposed on said pedestal wall portion of said first major surface adjacent said base region and extending from said source region to said drift region for controlling the conductivity of a channel portion of said base region extending between said source and drift regions; a collector electrode disposed on said second major surface in ohmic contact with said collector region; a source electrode disposed on said plateau portion of said first major surface in ohmic contact with said base region and said source region; and said base region comprising at least 40% of the area of said first major surface which is disposed in ohmic contact with said source electrode - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A UMOS IGBT comprising:
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a body of semiconductor material having first and second opposed major surfaces, said body including; a collector region of one type conductivity disposed adjacent said second major surface; a drift region of opposite type conductivity disposed adjacent said collector region and forming a first PN junction therewith; a base region of said one type conductivity disposed adjacent to said drift region, forming second PN junction therewith and being spaced from said collector region by said drift region; a source region of said opposite conductivity type forming a third PN junction with said base region and being spaced from said drift region by said base region; said base and source regions extending to a substantially planar portion of said first major surface; a trench structure extending into said semiconductor body from said planar portion of said first major surface whereby said first major surface includes a pedestal wall portion which bounds a pedestal structure comprise of said base and source regions; said base region including a channel portion disposed adjacent said pedestal wall portion of said first major surface and extending between said source region and said drift region; an insulated gate electrode disposed on said pedestal wall portion of said first major surface adjacent said channel portion of said base region and extending from said source region to said drift region for controlling the conductivity of said channel portion of said base region between said source and drift regions for carriers of said opposite conductivity type; a source region electrode disposed on said planar portion of said first major surface in ohmic contact with said base and source regions, the area of ohmic contact between said base region and said source region electrode being no less than two-thirds of the area of the ohmic contact between said source region and said source electrode; and a collector electrode disposed on said second major surface in ohmic contact with said collector region. - View Dependent Claims (25, 26, 27, 28, 29)
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Specification