Method of Manufacturing a Trench Transistor Having a Heavy Body Region
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Abstract
A trenched field effect transistor is provided that includes (a) a semiconductor substrate, (b) a trench extending a predetermined depth into the semiconductor substrate, (c) a pair of doped source junctions, positioned on opposite sides of the trench, (d) a doped heavy body positioned adjacent each source junction on the opposite side of the source junction from the trench, the deepest portion of the heavy body extending less deeply into said semiconductor substrate than the predetermined depth of the trench, and (e) a doped well surrounding the heavy body beneath the heavy body.
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Citations
67 Claims
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1-45. -45. (canceled)
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46. A method of manufacturing a trench transistor comprising:
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forming a plurality of trenches defined by a corresponding plurality of semiconductor mesas, a height of the plurality of mesas defining a depth of the plurality of trenches, the mesas having dopants of the first conductivity type; lining each of the plurality of trenches with a thin layer of gate dielectric material; substantially filling each dielectric-lined trench with conductive material to form a gate electrode of the transistor; forming a doped well in the plurality of mesas to a depth that is less than the depth of the plurality of trenches, the doped well having dopants of a second conductivity type opposite to said first conductivity type; forming a source region inside the doped well and extending to a depth that is less than the depth of the well, the source region having dopants of the first conductivity type; and forming a heavy body structure inside the doped well, the heavy body structure including a region having dopants of the second conductivity type with a peak concentration occurring at a peak concentration depth below the depth of the source region and above the depth of the doped well. - View Dependent Claims (47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 64, 65, 66)
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61-63. -63. (canceled)
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67-73. -73. (canceled)
Specification