Method of fabricating a semiconductor component with active regions separated by isolation trenches
First Claim
1. A method of fabricating a semiconductor component, comprising steps:
- a) forming at least one shallow trench in a semiconductor body;
b) after said step a), forming at least one deep trench within said at least one shallow trench in said semiconductor body;
c) providing at least one dopant; and
d) at the earliest after said step b), driving said at least one dopant into said semiconductor body to form at least one well respectively doped with said at least one dopant in said semiconductor body;
wherein said step d) comprises a thermally supported diffusion, at an elevated temperature, of said at least one dopant into said semiconductor body to form said at least one well.
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Abstract
To form a semiconductor component having active regions separated from one another by trenches as isolation structures, a method involves forming a shallow trench in a semiconductor body, thereafter forming a deep trench within the shallow trench in the semiconductor body, and thereafter completely driving dopant atoms into the semiconductor body to form a well region doped with the dopant. The dopant may be previously introduced by implantation into a surface layer, and then the dopant is finally completely driven into the well region by thermally supported diffusion after forming the deep trench. The shallow and deep trenches together form a compound trench with stepped side walls. Two oppositely doped wells may be formed on opposite sides of the compound trench, which thus isolates the two wells from one another. Active regions may be formed in the two wells.
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Citations
27 Claims
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1. A method of fabricating a semiconductor component, comprising steps:
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a) forming at least one shallow trench in a semiconductor body; b) after said step a), forming at least one deep trench within said at least one shallow trench in said semiconductor body; c) providing at least one dopant; and d) at the earliest after said step b), driving said at least one dopant into said semiconductor body to form at least one well respectively doped with said at least one dopant in said semiconductor body; wherein said step d) comprises a thermally supported diffusion, at an elevated temperature, of said at least one dopant into said semiconductor body to form said at least one well. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 26)
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24. A method of fabricating a semiconductor component, comprising, in sequence, steps:
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a) applying at least one mask leaving first and second open areas on a semiconductor body; b) implanting first and second dopants of opposite polarity respectively through said first and second open areas respectively into first and second surface regions of said semiconductor body; c) forming a shallow trench in said semiconductor body between and/or in said first and second surface regions; d) forming a deep trench within said shallow trench in said semiconductor body; e) forming a thin oxide layer on surfaces of said shallow trench and said deep trench; f) by a thermally supported diffusion process, driving said first and second dopants from said first and second surface regions deeper into said semiconductor body to respectively define first and second wells respectively doped with said first and second dopants on opposite sides of said shallow trench and said deep trench in said semiconductor body; and g) filling said shallow trench and said deep trench with an insulating material. - View Dependent Claims (25)
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27. A method of fabricating a semiconductor component, comprising steps:
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a) forming at least one shallow trench in a semiconductor body; b) after said step a), forming at least one deep trench within said at least one shallow trench in said semiconductor body; c) providing at least one dopant; and d) at the earliest after said step b), driving said at least one dopant into said semiconductor body to form at least one well respectively doped with said at least one dopant in said semiconductor body; wherein said semiconductor body comprises a silicon layer on an insulating layer, said step b) comprises forming said deep trench in said silicon layer to a trench depth reaching said insulating layer, and said step d) comprises forming said well in said silicon layer to a well depth reaching said insulating layer.
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Specification