Method for forming semiconductor device with buried gate structure
AssigneeNanya Technology Corporation
InventorChun-Chi Lai
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Abstract
A method for forming a semiconductor device includes forming a trench extending from a top surface of a semiconductor substrate into the semiconductor substrate, and forming a gate dielectric layer lining the trench. The method also includes forming a gate electrode layer in the trench and over the top surface of the semiconductor substrate. The formation of the gate electrode layer includes performing a first deposition process, performing a first etching process after the first deposition process, and performing a second deposition process after the first etching process.
Claims20
A method for forming a semiconductor device, comprising:
- forming a trench extending from a top surface of a semiconductor substrate into the semiconductor substrate;
- forming a gate dielectric layer lining the trench;
- and
- forming a gate electrode layer in the trench and over the top surface of the semiconductor substrate, wherein forming the gate electrode layer comprises:
- performing a first deposition process to deposit a gate electrode material in the trench and over the gate dielectric layer and the top surface of the semiconductor, wherein the gate electrode material in the trench includes top portions close to the top surface of the semiconductor and bottom portions away from the top surface of the semiconductor, wherein a thickness of the top portions is greater than a thickness of the bottom portions;
- performing a first etching process on the gate electrode material after the first deposition process;
- and
- performing a second deposition process after the first etching process.
A method for forming a semiconductor device, comprising:
- forming a trench extending from a top surface of a semiconductor substrate into the semiconductor substrate;
- forming a gate dielectric layer lining the trench;
- and
- forming a gate electrode layer in the trench and over the top surface of the semiconductor substrate, wherein forming the gate electrode layer comprises:
- depositing a first gate electrode material in the trench and over the gate dielectric layer and the top surface of the semiconductor substrate, wherein a first gap is surrounded by the first gate electrode material, wherein the gate electrode material in the trench includes top portions close to the top surface of the semiconductor and bottom portions away from the top surface of the semiconductor, wherein a thickness of the top portions is greater than a thickness of the bottom portions;
- and
- etching the first gate electrode material to widen the first gap such that a first opening is surrounded by a remaining portion of the first gate electrode material, wherein a top width of the first opening is greater than a top width of the first gap.
A method for forming a semiconductor device, comprising:
- forming a trench extending from a top surface of a semiconductor substrate into the semiconductor substrate;
- forming a gate dielectric layer lining the trench;
- and
- forming a gate electrode layer in the trench and over the top surface of the semiconductor substrate, wherein forming the gate electrode layer comprises:
- depositing a first gate electrode material in the trench and over the gate dielectric layer and the top surface of the semiconductor substrate, wherein a first gap is surrounded by the first gate electrode material, wherein the gate electrode material in the trench includes top portions close to the top surface of the semiconductor and bottom portions away from the top surface of the semiconductor, wherein a thickness of the top portions is greater than a thickness of the bottom portions;
- etching the first gate electrode material to reduce a thickness of the first gate electrode material in the trench and over the top surface of the semiconductor substrate;
- and
- depositing a second gate electrode material over a remaining portion of the first gate electrode material after the first gate electrode material is etched.
Dependencies are inferred from the claim text.