Gate and field electrode trench formation process
First Claim
1. A method of forming a semiconductor device, comprising:
- providing a semiconductor substrate comprising a main surface;
simultaneously forming an upper portion of a field electrode trench and a gate trench in the main surface of the substrate to approximately the same depth;
forming a first protective layer on the substrate, the first protective layer completely filling the gate trench and lining sidewalls of the upper portion of the field electrode trench, a bottom of the upper portion of the field electrode trench being exposed from the first protective layer;
removing semiconductor material from the exposed bottom of the upper portion of the field electrode trench thereby forming a lower portion of the field electrode trench while the gate trench remains completely filled by the first protective layer;
forming an electrically conductive field electrode and a field electrode dielectric in the upper and lower portions of the field electrode trench while the gate trench remains completely filled by the first protective layer;
removing at least some of the first protective layer from the gate trench;
forming a conformal gate dielectric layer that covers the field electrode and lines sidewalls of the gate trench after removing the at least some of the first protective layer; and
forming an electrically conductive gate electrode in the gate trench while the field electrode remains covered by the gate dielectric layer.
1 Assignment
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Accused Products
Abstract
An upper portion of a field electrode trench and a gate trench are simultaneously formed in the main surface of a substrate to approximately the same depth. A first protective layer is formed that completely fills the gate trench and lines the upper field electrode trench. The first protective layer is removed from the bottom of the upper trench and semiconductor material is removed thereby forming a lower portion of the field electrode trench while the gate trench remains completely filled by the first protective layer. An electrically conductive field electrode and a field electrode dielectric are formed in the field electrode trench. At least some of the first protective layer is removed from the gate trench. A conformal gate dielectric layer is formed on the substrate. An electrically conductive gate electrode is formed in the gate trench while the field electrode remains covered by the gate dielectric layer.
6 Citations
20 Claims
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1. A method of forming a semiconductor device, comprising:
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providing a semiconductor substrate comprising a main surface; simultaneously forming an upper portion of a field electrode trench and a gate trench in the main surface of the substrate to approximately the same depth; forming a first protective layer on the substrate, the first protective layer completely filling the gate trench and lining sidewalls of the upper portion of the field electrode trench, a bottom of the upper portion of the field electrode trench being exposed from the first protective layer; removing semiconductor material from the exposed bottom of the upper portion of the field electrode trench thereby forming a lower portion of the field electrode trench while the gate trench remains completely filled by the first protective layer; forming an electrically conductive field electrode and a field electrode dielectric in the upper and lower portions of the field electrode trench while the gate trench remains completely filled by the first protective layer; removing at least some of the first protective layer from the gate trench; forming a conformal gate dielectric layer that covers the field electrode and lines sidewalls of the gate trench after removing the at least some of the first protective layer; and forming an electrically conductive gate electrode in the gate trench while the field electrode remains covered by the gate dielectric layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of forming a semiconductor device, comprising:
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providing a semiconductor substrate comprising a main surface; forming a field electrode trench comprising a dielectrically insulated field electrode and a gate trench comprising a dielectrically insulated gate electrode in the substrate, the field electrode trench being wider and deeper than the gate trench, the gate trench being longer than the field electrode trench, wherein forming the field electrode trench comprising the dielectrically insulated field electrode and the gate trench comprising a dielectrically insulated gate electrode comprises; forming an upper portion of the field electrode trench and the gate trench simultaneously; forming a first protective layer that completely fills the gate trench; removing semiconductor material from a bottom of the upper portion of the field electrode trench thereby forming a lower portion of the field electrode trench while the gate trench remains completely filled by the first protective layer; forming an electrically conductive field electrode and a field electrode dielectric in the upper and lower portions of the field electrode trench while the gate trench remains completely filled by the first protective layer; removing at least some of the first protective layer from the gate trench; covering the field electrode with a second protective layer; and forming an electrically conductive gate electrode and a gate trench dielectric in the gate trench while the field electrode remains covered by the second protective layer. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification