METHOD OF FORMING A SEMICONDUCTOR DEVICE HAVING A PATTERNED GATE DIELECTRIC AND STRUCTURE THEREFOR
First Claim
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1. A method of forming an insulated gate semiconductor device comprising the steps of:
- providing a region of semiconductor material having a major surface;
forming a first trench extending from the major surface into the region of semiconductor material;
forming a first dielectric layer overlying surfaces of the first trench;
forming a photosenstive layer overlying the first dielectric layer, wherein the photosensitive layer is configured to protect at least a portion of the first dielectric layer along lower surfaces of the first trench;
removing at least a portion of the first dielectric layer from at least one upper sidewall surface of the first trench;
removing the photosensitive layer;
forming a second dielectric layer along the at least one upper sidewall surface, wherein the first and second dielectric layers have different thicknesses; and
forming a first conductive electrode along at least one of the first and second dielectric layers.
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Abstract
In one embodiment, a semiconductor device includes an isolated trench-electrode structure. The semiconductor device is formed using a modified photolithographic process to produce alternating regions of thick and thin dielectric layers that separate the trench electrode from regions of the semiconductor device. The thin dielectric layers can be configured to control the formation channel regions, and the thick dielectric layers can be configured to reduce switching losses.
61 Citations
21 Claims
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1. A method of forming an insulated gate semiconductor device comprising the steps of:
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providing a region of semiconductor material having a major surface; forming a first trench extending from the major surface into the region of semiconductor material; forming a first dielectric layer overlying surfaces of the first trench; forming a photosenstive layer overlying the first dielectric layer, wherein the photosensitive layer is configured to protect at least a portion of the first dielectric layer along lower surfaces of the first trench; removing at least a portion of the first dielectric layer from at least one upper sidewall surface of the first trench; removing the photosensitive layer; forming a second dielectric layer along the at least one upper sidewall surface, wherein the first and second dielectric layers have different thicknesses; and forming a first conductive electrode along at least one of the first and second dielectric layers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An insulated gate semiconductor device structure comprising:
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a region of semiconductor material having a major surface; a first trench extending from the major surface; a second trench extending from the major surface and spaced apart from the first trench; a first dielectric layer formed along lower surfaces of both the first and second trenches and at least a portion of a first upper surface of both the first and second trenches; a second dielectric layer formed along at least a portion of a second upper surface of both the first and second trenches, wherein the second dielectric layer is thinner than the first dielectric layer; a first conductive electrode formed within the first trench along the first and second dielectric layers; and a second conductive electrode formed within the second trench along the first and second dielectric layers, wherein the first and second conductive electrodes and the second dielectric layer are configured to control a channel region within the region of semiconductor material. - View Dependent Claims (15, 16)
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18. A method for forming a semiconductor device comprising:
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providing a region of semiconductor material having a major surface; forming a first and second trenches extending from the major surface and spaced apart; forming a first doped region within the region of semiconductor material; forming a first layer along surfaces of the first and second trenches and along the major surface; forming a photosensitive layer overlying the first layer; forming openings in the photosensitive layer to expose the first layer along portions of upper sidewall surfaces of the first and second trenches and along portions of the major surface; reducing the thickness of the exposed portions of the first layer, wherein other portions of the first layer remain along lower surfaces of the first and second trenches and the major surface; forming a second layer where the first layer was reduced in thickness, wherein the second layer is thinner than the first layer; and forming conductive electrodes in the first and second trenches along the first and second layers. - View Dependent Claims (17, 19, 20)
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21. A method for forming an insulated gate semiconductor device comprising:
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forming a trench extending from a major surface of a region of semiconductor material; forming a first dielectric layer along surfaces of the trench; providing a patterned layer overlying the first dielectric layer including a plurality of laterally spaced apart openings along an upper surface of the trench; reducing the thickness of the first dielectric layer through the openings while leaving other portions of the first dielectric layer in place along other surfaces of the trench adjacent the openings; forming a second dielectric layer along those portions of the trench where the first dielectric layer was reduced in thickness; forming a control electrode adjacent the first and second dielectric layers within the trench, wherein the second dielectric layer is configured as a gate dielectric layer and the first dielectric layer is thicker than the second dielectric layer.
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Specification