Method of forming a FET having ultra-low on-resistance and low gate charge
First Claim
1. A method of forming a field effect transistor, comprising:
- providing a substrate of a first conductivity type silicon;
forming a substrate cap region of the first conductivity type silicon such that a junction is formed between the substrate cap region and the substrate;
forming a body region of a second conductivity type silicon such that a junction is formed between the body region and the substrate cap region;
forming a trench extending through at least the body region; and
forming a source region of the first conductivity type in an upper portion of the body region,wherein during one or more temperature cycles, dopants of the first conductivity type in the substrate cap region out-diffuse into a lower portion of the body region to thereby form an out-diffusion region of the first conductivity type in the lower portion of the body region such that a spacing between the source region and the substrate out-diffusion region defines a length of a channel region of the field effect transistor.
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Accused Products
Abstract
In accordance with an exemplary embodiment of the invention, a substrate of a first conductivity type silicon is provided. A substrate cap region of the first conductivity type silicon is formed such that a junction is formed between the substrate cap region and the substrate. A body region of a second conductivity type silicon is formed such that a junction is formed between the body region and the substrate cap region. A trench extending through at least the body region is then formed. A source region of the first conductivity type is then formed in an upper portion of the body region. An out-diffusion region of the first conductivity type is formed in a lower portion of the body region as a result of one or more temperature cycles such that a spacing between the source region and the out-diffusion region defines a channel length of the field effect transistor.
265 Citations
30 Claims
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1. A method of forming a field effect transistor, comprising:
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providing a substrate of a first conductivity type silicon; forming a substrate cap region of the first conductivity type silicon such that a junction is formed between the substrate cap region and the substrate; forming a body region of a second conductivity type silicon such that a junction is formed between the body region and the substrate cap region; forming a trench extending through at least the body region; and forming a source region of the first conductivity type in an upper portion of the body region, wherein during one or more temperature cycles, dopants of the first conductivity type in the substrate cap region out-diffuse into a lower portion of the body region to thereby form an out-diffusion region of the first conductivity type in the lower portion of the body region such that a spacing between the source region and the substrate out-diffusion region defines a length of a channel region of the field effect transistor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A field effect transistor, comprising:
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a substrate of a first conductivity type silicon; a substrate cap region of the first conductivity type silicon forming a junction with the substrate; a body region of a second conductivity type silicon over and in contact with the substrate cap region; a trench extending at least through the body region; a source region of the first conductivity type formed in an upper portion of the body region; and an out-diffusion region of the first conductivity type formed in a lower portion of the body region such that a spacing between the source region and the out-diffusion region defines a channel length of the field effect transistor. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification