Semiconductor device including a transistor with a gate dielectric having a variable thickness
First Claim
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1. A semiconductor device comprising a transistor in a semiconductor substrate having a main surface, the transistor comprising:
- a source region;
a drain region laterally spaced apart from the source region;
a channel region and a drift zone each being laterally disposed between the source and drain regions;
a gate trench formed in the main surface of the semiconductor substrate;
an electrically conductive gate electrode formed in the gate trench;
a gate dielectric formed in the gate trench and electrically insulating the gate electrode from the semiconductor substrate,wherein the gate trench comprises;
first, second, third and fourth sidewalls and a bottom surface, the first sidewall extending though and facing the source region, the second sidewall extending through and facing the drift zone, and third and fourth sidewalls each extending through and facing the channel region and each extending from the first sidewall to the second sidewall,wherein the second sidewall is laterally spaced apart from the drain region by a portion of the drift zone, andwherein a first thickness of the gate dielectric as measured between the gate electrode and the second sidewall is greater than a second thickness of the gate dielectric as measured between the gate electrode and the first sidewall.
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Abstract
A semiconductor device includes a transistor in a semiconductor substrate having a main surface. The transistor includes a source region, a drain region, a channel region, a drift zone, a gate electrode, and a gate dielectric adjacent to the gate electrode. The gate electrode is disposed adjacent to at least two sides of the channel region. The channel region and the drift zone are disposed along a first direction parallel to the main surface between the source region and the drain region. The gate dielectric has a thickness that varies at different positions of the gate electrode.
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Citations
10 Claims
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1. A semiconductor device comprising a transistor in a semiconductor substrate having a main surface, the transistor comprising:
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a source region; a drain region laterally spaced apart from the source region; a channel region and a drift zone each being laterally disposed between the source and drain regions; a gate trench formed in the main surface of the semiconductor substrate; an electrically conductive gate electrode formed in the gate trench; a gate dielectric formed in the gate trench and electrically insulating the gate electrode from the semiconductor substrate, wherein the gate trench comprises;
first, second, third and fourth sidewalls and a bottom surface, the first sidewall extending though and facing the source region, the second sidewall extending through and facing the drift zone, and third and fourth sidewalls each extending through and facing the channel region and each extending from the first sidewall to the second sidewall,wherein the second sidewall is laterally spaced apart from the drain region by a portion of the drift zone, and wherein a first thickness of the gate dielectric as measured between the gate electrode and the second sidewall is greater than a second thickness of the gate dielectric as measured between the gate electrode and the first sidewall. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A semiconductor device comprising a transistor in a semiconductor substrate having a main surface, the transistor comprising:
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a source region; a drain region laterally spaced apart from the source region; a channel region and a drift zone each being laterally disposed between the source and drain regions; a plurality of gate trenches formed in the main surface of the semiconductor substrate, an electrically conductive electrode formed in each of the gate trenches, a gate dielectric formed in each of the gate trenches, the gate dielectric electrically insulating each gate electrode from the semiconductor substrate; a plurality of field plate trenches formed in the main surface of the semiconductor substrate; an electrically conductive field plate formed in each of the field plate trenches; a gate dielectric formed in each of the gate trenches, the gate dielectric electrically insulating each field plate from the semiconductor substrate, wherein each of the gate trenches extend in a first lateral direction from the source region through the channel region to reach the drift zone, wherein each of the field plate trenches are disposed within the drift zone and laterally separated from each of the gate trenches in the first lateral direction, wherein a pitch of the gate trenches is smaller than a pitch of the field plate trenches, the pitch of the gate trenches and field plate trenches being measured in a second lateral direction of the semiconductor device, the second lateral direction being perpendicular to the first lateral direction and parallel to the main surface. - View Dependent Claims (9, 10)
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Specification