Isolation structures and methods of forming the same
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsShih-Wei Lin, Hau-Yan Lu, Te-Hsien Hsieh
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Abstract
Depositing an oxide material on sidewalls of trenches between etching cycles allows narrower trenches to be etched to increased depths without causing over-etching of wider trenches. As a result, efficiency of a device including the trenches (e.g., a silicon photonics (SiPh) device or a pixel device, among other examples) is increased. For example, because light leakage and light scattering is reduced in an SiPh device, power is conserved at a transmission device that can decrease transmit power on account of the increased efficiency.
Claims20
A semiconductor structure, comprising:
- at least one etch stop layer (ESL);
- and
- a silicon operational structure, over the at least one ESL, that includes a first isolation structure associated with a first width and a second isolation structure associated with a second width larger than the first width,
- wherein sidewall surfaces of the first isolation structure include a scallop profile, and
- wherein the first isolation structure extends into the at least one ESL and has a bottom surface located lower than a bottom surface of the second isolation structure.
A semiconductor structure, comprising:
- at least one etch stop layer (ESL);
- a silicon operational structure over the at least one ESL that includes a first isolation structure associated with a first width and a second isolation structure associated with a second width larger than the first width, wherein the first isolation structure extends into the at least one ESL and has a bottom surface located lower than a bottom surface of the second isolation structure;
- and
- an oxide material on sidewall surfaces of the first isolation structure and the second isolation structure and absent from the bottom surface of the first isolation structure and the bottom surface of the second isolation structure.
A semiconductor structure, comprising:
- a silicon layer that includes:
- a first trench associated with a first width and a first depth, and
- a second trench associated with a second width, larger than the first width, and a second depth less than the first depth;
- an oxide material on sidewalls of the first trench and the second trench,
- wherein the oxide material is absent from a bottom surface of the first trench and the second trench;
- and
- a supporting layer, wherein:
- the silicon layer resides over the supporting layer, and
- at least one of:
- the first trench extends into the supporting layer, or
- the second trench resides directly on a top surface of the supporting layer.
Dependencies are inferred from the claim text.