Method of forming a trench transistor having a superior gate dielectric
First Claim
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1. A method of forming a trench field-effect transistor, the method comprising the steps of:
- forming a trench in silicon on a substrate;
forming a gate dielectric layer inside the trench, comprising the steps of;
heating the substrate to at least about 1,100°
C. to form a first layer of silicon oxide at least about 100 Å
thick inside the trench; and
forming a layer of silicon nitride on the first layer of silicon oxide.
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Abstract
A trench transistor with lower leakage current and higher gate rupture voltage. The gate oxide layer of a trench transistor is grown at a temperature above about 1100° C. to reduce thinning of the oxide layer at the corners of the trench. In a further embodiment, a conformal layer of silicon nitride is deposited over the high-temperature oxide layer, and a second oxide layer is formed between the silicon nitride layer and the gate polysilicon. The first gate oxide layer, silicon nitride layer, and second oxide layer form a composite gate dielectric structure that substantially reduces leakage current in trench field effect transistors.
16 Citations
9 Claims
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1. A method of forming a trench field-effect transistor, the method comprising the steps of:
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forming a trench in silicon on a substrate;
forming a gate dielectric layer inside the trench, comprising the steps of;
heating the substrate to at least about 1,100°
C. to form a first layer of silicon oxide at least about 100 Å
thick inside the trench; and
forming a layer of silicon nitride on the first layer of silicon oxide. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of forming trench field-effect transistor, the method comprising:
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forming a trench in silicon on a substrate;
forming a gate dielectric layer inside the trench, comprising the steps of;
heating the substrate to at least about 1,100°
C. to form a first layer of silicon oxide at least about 100 Å
thick in the trench;
forming a conformal layer of silicon nitride about 120 Å
thick on the layer of silicon oxide by a low-pressure chemical-vapor deposition process;
growing a second layer of oxide about 50 Å
thick on the layer of silicon nitride; and
forming a conductive gate material on the second layer of oxide. - View Dependent Claims (9)
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Specification