Method for fabricating trench power device
First Claim
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1. A method for forming an oxide layer at the bottom of a trench, the method comprising:
- providing a first substrate with at least one trench therein;
forming a first oxide layer on the bottom and sidewalls of the trench;
removing the first oxide layer at the bottom of the trench to expose the bottom of the trench; and
forming a second oxide layer at the bottom of the trench;
wherein the second oxide layer is formed by chemical vapor deposition (CVD) of ozone-tetraethyloxysilane (O3-TEOS) having a sufficiently high ratio of a flow rate of ozone to a flow rate of TEOS so as to form the second oxide layer on the exposed bottom of the trench and without forming the second oxide layer on the first oxide layer and on the first substrate.
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Abstract
Embodiments of the invention relate to a fabrication method of an electronic device, more particularly to a fabrication method of a power device in which an oxide layer at the bottom of the trench is provided to reduce Miller capacitance and further reduce RC delay. In one embodiment, a method for forming an oxide layer at the bottom of a trench comprises providing a first substrate with at least one trench therein; forming a first oxide layer on the bottom and sidewalls of the trench; removing the first oxide layer at the bottom of the trench; and forming a second oxide layer at the bottom of the trench.
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52 Claims
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1. A method for forming an oxide layer at the bottom of a trench, the method comprising:
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providing a first substrate with at least one trench therein; forming a first oxide layer on the bottom and sidewalls of the trench; removing the first oxide layer at the bottom of the trench to expose the bottom of the trench; and forming a second oxide layer at the bottom of the trench; wherein the second oxide layer is formed by chemical vapor deposition (CVD) of ozone-tetraethyloxysilane (O3-TEOS) having a sufficiently high ratio of a flow rate of ozone to a flow rate of TEOS so as to form the second oxide layer on the exposed bottom of the trench and without forming the second oxide layer on the first oxide layer and on the first substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for fabricating a power device, the method comprising:
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providing a substrate; forming a third oxide layer on the substrate; forming a silicon nitride layer on the third oxide layer; patterning the silicon nitride layer and the third oxide layer to form an opening; etching the substrate along the opening to form a trench therein; forming a first oxide layer on the bottom and sidewalls of the trench; removing the first oxide layer at the bottom of the trench to expose the bottom of the trench; and forming a second oxide layer at the bottom of the trench; wherein the second oxide layer is formed by chemical vapor deposition (CVD) of ozone-tetraethyloxysilane (O3-TEOS) having a sufficiently high ratio of a flow rate of ozone to a flow rate of TEOS so as to form the second oxide layer on the exposed bottom of the trench and without forming the second oxide layer on the first oxide layer, on the third oxide layer, and on the silicon nitride layer. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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36. A method for fabricating a power device, the method comprising:
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providing a substrate; forming a third oxide layer on the substrate; forming a silicon nitride layer on the third oxide layer; patterning the silicon nitride layer and the third oxide layer to form an opening; etching the substrate along the opening to form a trench therein; forming a first oxide layer on the bottom and sidewalls of the trench; removing the first oxide layer at the bottom of the trench to expose the bottom of the trench; forming a second oxide layer at the bottom of the trench; removing the remaining silicon nitride layer; and removing the first oxide on the sidewalls of the trench and the remaining third oxide layer; wherein the second oxide layer is formed by chemical vapor deposition (CVD) of ozone-tetraethyloxysilane (O3-TEOS) having a sufficiently high ratio of a flow rate of ozone to a flow rate of TEOS so as to form the second oxide layer on the exposed bottom of the trench and without forming the second oxide layer on the first oxide layer and on the first substrate. - View Dependent Claims (37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52)
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Specification