Forming switch circuit with controllable phase node ringing
First Claim
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1. A method for forming a switch circuit, comprising:
- forming an array of trench transistor cells in a semiconductor layer of a first conductivity type, the trench transistor cells being defined by trench gate structures, each of said gate trench structures including a trench formed in the semiconductor layer and an insulated gate electrode formed in the trench;
forming first body regions of a second conductivity type that is opposite the first conductivity type in a first subset of the trench transistor cells, the first body regions and trenches of the first subset of the trench transistor cells being characterized by a first distance from a bottom of the first body regions to a bottom of the gate trenches in the first subset associated with a first reverse gate-to-drain capacitance (Crss);
forming second body regions of the second conductivity type that is opposite the first conductivity type in a second subset of the trench transistor cells, the second body regions and trenches of the second subset of the trench transistor cells being characterized by a second distance from a bottom of the second body regions to a bottom of the gate trenches in the second subset associated with a second reverse gate-to-drain capacitance (Crss), wherein the second distance is greater than the first distance; and
forming source regions in the array of trench transistor cells.
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Abstract
A switch circuit includes a first MOS transistor and a second MOS transistor of a same conductivity type connected in parallel between a first terminal and a second terminal of the switch circuit, the first and second MOS transistors having respective gate terminals coupled to the control terminal to receive a control signal to turn the first and second MOS transistors on or off. The first MOS transistor is characterized by a first reverse gate-to-drain capacitance (Crss) and the second MOS transistor is characterized by a second Crss that is greater than the first Crss.
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11 Claims
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1. A method for forming a switch circuit, comprising:
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forming an array of trench transistor cells in a semiconductor layer of a first conductivity type, the trench transistor cells being defined by trench gate structures, each of said gate trench structures including a trench formed in the semiconductor layer and an insulated gate electrode formed in the trench; forming first body regions of a second conductivity type that is opposite the first conductivity type in a first subset of the trench transistor cells, the first body regions and trenches of the first subset of the trench transistor cells being characterized by a first distance from a bottom of the first body regions to a bottom of the gate trenches in the first subset associated with a first reverse gate-to-drain capacitance (Crss); forming second body regions of the second conductivity type that is opposite the first conductivity type in a second subset of the trench transistor cells, the second body regions and trenches of the second subset of the trench transistor cells being characterized by a second distance from a bottom of the second body regions to a bottom of the gate trenches in the second subset associated with a second reverse gate-to-drain capacitance (Crss), wherein the second distance is greater than the first distance; and forming source regions in the array of trench transistor cells. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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