Superjunction power semiconductor device and method for forming
First Claim
1. A method for manufacturing a super junction power MOSFET comprising:
- forming a first trench in a semiconductor substrate;
forming a first oxide layer over the semiconductor substrate and in the first trench, wherein the first oxide layer is along a bottom and sidewalls of the first trench;
depositing electrically conductive material in the first trench to form a first shield electrode;
masking a first portion of the electrically conductive material in the first trench;
forming a recessed portion of the electrically conductive material (44) by removing a part of a second portion of the electrically conductive material while the first portion of the electrically conductive material is masked;
forming an oxide portion over and in contact with the recessed portion of the electrically conductive material;
removing a part of the oxide portion in the first trench;
removing the first oxide layer on the sidewalls of the trench while another part of the oxide portion remains in contact with the recessed portion of the electrically conductive material;
forming a gate dielectric along exposed sidewalls of the first trench; and
depositing additional electrically conductive material over the other part of the oxide portion in the first trench,wherein the removing the part of the oxide portion in the first trench includes masking the substrate with a second mask that includes an opening over the first trench that covers the gate dielectric and exposes a central portion of the oxide portion.
1 Assignment
0 Petitions
Accused Products
Abstract
A method for manufacturing a super junction power MOSFET includes forming a first trench in a substrate, forming a first oxide layer over the substrate and in the bottom and along sidewalls of the trench, depositing electrically conductive material in the trench, masking a first portion of the electrically conductive material, forming a recessed portion of the electrically conductive material, forming an oxide portion over and in contact with the recessed portion of the electrically conductive material, removing a part of the oxide portion by masking, removing the first oxide layer on the sidewalls while another part of the oxide portion remains in contact with the recessed portion of the electrically conductive material, forming a gate dielectric along exposed sidewalls of the trench, and depositing additional electrically conductive material over the other part of the oxide portion in the trench.
9 Citations
19 Claims
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1. A method for manufacturing a super junction power MOSFET comprising:
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forming a first trench in a semiconductor substrate; forming a first oxide layer over the semiconductor substrate and in the first trench, wherein the first oxide layer is along a bottom and sidewalls of the first trench; depositing electrically conductive material in the first trench to form a first shield electrode; masking a first portion of the electrically conductive material in the first trench; forming a recessed portion of the electrically conductive material (44) by removing a part of a second portion of the electrically conductive material while the first portion of the electrically conductive material is masked; forming an oxide portion over and in contact with the recessed portion of the electrically conductive material; removing a part of the oxide portion in the first trench; removing the first oxide layer on the sidewalls of the trench while another part of the oxide portion remains in contact with the recessed portion of the electrically conductive material; forming a gate dielectric along exposed sidewalls of the first trench; and depositing additional electrically conductive material over the other part of the oxide portion in the first trench, wherein the removing the part of the oxide portion in the first trench includes masking the substrate with a second mask that includes an opening over the first trench that covers the gate dielectric and exposes a central portion of the oxide portion. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of making a semiconductor device comprising:
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forming a first mask over a semiconductor substrate, wherein the substrate includes a major surface covered with a nitride material, a first trench and a second trench in the major surface, the first and second trenches include a dielectric material along respective sidewalls and are filled with a first polysilicon material, and the first mask is configured to completely cover the first trench and only a portion of the second trench; removing a portion of the first polysilicon material from an unmasked portion of the second trench; removing the first mask; depositing a second dielectric material that fills the first and second trenches; forming a second mask over the nitride material on the substrate with an opening over the second trench, wherein the second mask overhangs a portion of the second dielectric material in the second trench; removing an unmasked portion of the second dielectric material in the second trench so that some of the second dielectric material remains over the first polysilicon material in the second trench and along the sidewalls of the second trench to form first and second shield electrodes; removing the second dielectric material along the sidewalls of the second trench while the some of the second dielectric material remains over the first polysilicon material in the second trench; removing the second mask; forming a third dielectric material along the sidewalls of the second trench; and filling the second trench with a second polysilicon material to form a first gate electrode. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification