Integrated Hydrogen Anneal and Gate Oxidation for Improved Gate Oxide Integrity
First Claim
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1. A method for forming a trench gate field effect transistor, comprising:
- forming trenches in a semiconductor substrate;
annealing the semiconductor substrate in an ambient including hydrogen gas;
forming a dielectric layer lining at least the sidewalls of the trenches; and
during the time between the annealing and forming the dielectric layer, maintaining the semiconductor substrate in an inert environment to prevent formation of native oxide along sidewalls of the trenches prior to forming the dielectric layer.
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Abstract
A method of forming a trench gate field effect transistor includes the following processing steps. Trenches are formed in a semiconductor substrate. The semiconductor substrate is annealed in an ambient including hydrogen gas. A dielectric layer lining at least the sidewalls of the trenches is formed. During the time between annealing and forming the dielectric layer, the semiconductor substrate is maintained in an inert environment to prevent formation of native oxide along sidewalls of the trenches prior to forming the dielectric layer.
30 Citations
32 Claims
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1. A method for forming a trench gate field effect transistor, comprising:
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forming trenches in a semiconductor substrate; annealing the semiconductor substrate in an ambient including hydrogen gas; forming a dielectric layer lining at least the sidewalls of the trenches; and during the time between the annealing and forming the dielectric layer, maintaining the semiconductor substrate in an inert environment to prevent formation of native oxide along sidewalls of the trenches prior to forming the dielectric layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for forming a trench gate field effect transistor, comprising:
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forming trenches in a semiconductor substrate of a first conductivity type; annealing the semiconductor substrate in an ambient including hydrogen gas; performing an oxidation process to form a layer of gate oxide along the sidewalls of the trenches; during the time between the annealing and performing an oxidation process, maintaining the semiconductor substrate in an inert environment to prevent formation of native oxide along sidewalls of the trenches prior to forming the layer of gate oxide; forming a gate electrode in each trench; forming a well region of a second conductivity type in the semiconductor substrate; forming source regions of the first conductivity type in the well region; and forming heavy body regions of the second conductivity type in the well region. - View Dependent Claims (13, 14)
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15. A method of forming a shielded gate field effect transistor, comprising:
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forming trenches in a semiconductor substrate; forming a shield dielectric layer lining lower sidewalls and bottom of each trench; forming a shield electrode filling a bottom portion of each trench; annealing the semiconductor substrate in an ambient including hydrogen gas; forming a dielectric layer lining at least the upper sidewalls of each trench; during the time between the annealing and forming the dielectric layer, maintaining the semiconductor substrate in an inert environment to prevent formation of native oxide along upper sidewalls of each trench prior to forming the dielectric layer; and forming a gate electrode in an upper portion of each trench. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method of forming a shielded gate field effect transistor, comprising:
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forming trenches in a semiconductor substrate of a first conductivity type; forming a shield dielectric layer lining lower sidewalls and bottom of each trench; forming a shield electrode filling a bottom portion of each trench; annealing the semiconductor substrate in an ambient including hydrogen gas; performing an oxidation process to form a layer of gate oxide along upper sidewalls of each trench; during the time between the annealing and performing an oxidation process, maintaining the semiconductor substrate in an inert environment to prevent formation of native oxide along upper sidewalls of each trench prior to forming the layer of gate oxide; forming a gate electrode in an upper portion of each trench; forming a well region of a second conductivity type in the semiconductor substrate; forming source regions of the first conductivity type in the well region; and forming heavy body regions of the second conductivity type in the well region. - View Dependent Claims (28, 29, 30, 31)
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32-40. -40. (canceled)
Specification