Low resistivity deep trench fill for DRAM and EDRAM applications
First Claim
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1. A method of fabricating a semiconductor device comprising:
- (a) forming a trench in a semiconductor substrate, the trench including sidewalls defining a trench depth and a top opening defining a trench width, the sidewalls being substantially covered with a dielectric material; and
(b) depositing fill material having a resistivity below 5000 μ
Ω
·
cm on the dielectric material within the trench by flowing a first gas and a second gas together over the trench at a selected temperature and pressure, the first gas including a base material and the second gas including a dopant, wherein flowing the first and second gases together facilitates in situ doping of the base material.
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Abstract
Semiconductor devices having deep trenches with fill material therein having low resistivity are provided along with methods of fabricating such semiconductor devices.
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Citations
38 Claims
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1. A method of fabricating a semiconductor device comprising:
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(a) forming a trench in a semiconductor substrate, the trench including sidewalls defining a trench depth and a top opening defining a trench width, the sidewalls being substantially covered with a dielectric material; and
(b) depositing fill material having a resistivity below 5000 μ
Ω
·
cm on the dielectric material within the trench by flowing a first gas and a second gas together over the trench at a selected temperature and pressure, the first gas including a base material and the second gas including a dopant, wherein flowing the first and second gases together facilitates in situ doping of the base material.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of fabricating a semiconductor device comprising:
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(a) forming a trench in a semiconductor substrate, the trench including sidewalls defining a trench depth and a top opening defining a trench width, the sidewalls being substantially covered by a dielectric material;
(b) forming a layer of fill material having a resistivity below about 5000 μ
Ω
·
cm on the dielectric material at a first temperature and a first pressure, the fill material being formed by depositing a base layer having a thickness less than 50 nm on the dielectric material; and
(c) soaking the base layer with a gas containing a dopant at a second temperature and a second pressure until the base layer is coated with the dopant. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method of fabricating a semiconductor device comprising:
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(a) forming a trench in a semiconductor substrate, the trench including sidewalls defining a trench depth and a top opening defining a trench width, the sidewalls being substantially covered by a dielectric material;
(b) forming a layer of fill material having a resistivity of below about 5000 μ
Ω
·
cm on the dielectric material at a first temperature and a first pressure, the fill material being formed by depositing a base layer having a thickness less than 50 nm; and
(c) diffusing a dopant into the base layer at a second temperature and a second pressure. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31)
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32. A method of fabricating a semiconductor device comprising:
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(a) forming a trench in a semiconductor substrate, the trench including sidewalls defining a trench depth and a top opening defining a trench width, the sidewalls being substantially covered by a dielectric material;
(b) forming a first fill material including a light dopant over the dielectric material in a lower region of the trench;
(c) forming a second fill material including a heavy dopant in an upper region of the trench, wherein the second fill material reduces diffusion of the light dopant out of the trench, and the combination of the first and second fill materials has a resistivity of below about 5000 μ
Ω
·
cm.- View Dependent Claims (33, 34, 35, 36, 37, 38)
forming the first fill material includes flowing a first base gas and a first dopant gas together over the trench at a first selected temperature and pressure, the first base gas including a first base material and the first dopant gas including the light dopant, wherein flowing the first base gas and the first dopant gas together facilitates in situ doping of the first base material; and
forming the second fill material includes flowing a second base gas and a second dopant gas together over the trench at a second selected temperature and pressure, the second base gas including a second base material and the second dopant gas including the heavy dopant, wherein flowing the second base gas and the second dopant gas together facilitates in situ doping of the second base material.
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34. The method according to claim 32, wherein:
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forming the first fill material includes depositing a first base layer on the dielectric material and soaking the first base layer with a first dopant gas containing the light dopant at a first selected temperature and pressure until the first base layer is coated with the light dopant; and
forming the second fill material includes depositing a second base layer over the first fill material and soaking the second base layer with a second dopant gas containing the heavy dopant at a second selected temperature and pressure until the second base layer is coated with the heavy dopant.
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35. The method according to claim 32, wherein:
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forming the first fill material includes depositing a first base layer on the dielectric material and diffusing the light dopant into the first base layer at a first selected temperature and pressure; and
forming the second fill material includes depositing a second base layer over the first fill material and diffusing the heaving dopant into the second base layer at a second selected temperature and pressure.
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36. The method according to claim 32, further including:
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forming a capping layer over the second fill material; and
annealing the semiconductor substrate to diffuse the light and heavy dopants.
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37. The method according to claim 32, wherein the light dopant comprises P and the heavy dopant comprises As.
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38. The method according to claim 32, wherein the light dopant comprises P and the heavy dopant comprises Sb.
Specification